diff --git a/browser/base/content/browser-places.js b/browser/base/content/browser-places.js
index fcaab9ede964..c9cba5bc0c75 100644
--- a/browser/base/content/browser-places.js
+++ b/browser/base/content/browser-places.js
@@ -128,6 +128,13 @@ var StarUI = {
             }
             this.panel.hidePopup();
             break;
+          // This case is for catching character-generating keypresses
+          case 0:
+            let accessKey = document.getElementById("key_close");
+            if (eventMatchesKey(aEvent, accessKey)) {
+                this.panel.hidePopup();
+            }
+            break;
         }
         break;
       case "mouseout":
diff --git a/browser/base/content/browser.js b/browser/base/content/browser.js
index e0c737f3de71..d4adf5fc1fc4 100755
--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -1367,6 +1367,15 @@ var gBrowserInit = {
 
       PanicButtonNotifier.init();
     });
+
+    gBrowser.tabContainer.addEventListener("TabSelect", function() {
+      for (let panel of document.querySelectorAll("panel[tabspecific='true']")) {
+        if (panel.state == "open") {
+          panel.hidePopup();
+        }
+      }
+    });
+
     this.delayedStartupFinished = true;
 
     Services.obs.notifyObservers(window, "browser-delayed-startup-finished", "");
@@ -6613,10 +6622,18 @@ var gIdentityHandler = {
     return this._identityPopupInsecureLoginFormsLearnMore =
       document.getElementById("identity-popup-insecure-login-forms-learn-more");
   },
+  get _identityIconLabels () {
+    delete this._identityIconLabels;
+    return this._identityIconLabels = document.getElementById("identity-icon-labels");
+  },
   get _identityIconLabel () {
     delete this._identityIconLabel;
     return this._identityIconLabel = document.getElementById("identity-icon-label");
   },
+  get _connectionIcon () {
+    delete this._connectionIcon;
+    return this._connectionIcon = document.getElementById("connection-icon");
+  },
   get _overrideService () {
     delete this._overrideService;
     return this._overrideService = Cc["@mozilla.org/security/certoverride;1"]
@@ -6905,7 +6922,6 @@ var gIdentityHandler = {
         // pages, either already insecure or with mixed active content loaded.
         this._identityBox.classList.add("insecureLoginForms");
       }
-      tooltip = gNavigatorBundle.getString("identity.unknown.tooltip");
     }
 
     if (this._isCertUserOverridden) {
@@ -6944,7 +6960,8 @@ var gIdentityHandler = {
     }
 
     // Push the appropriate strings out to the UI
-    this._identityBox.tooltipText = tooltip;
+    this._connectionIcon.tooltipText = tooltip;
+    this._identityIconLabels.tooltipText = tooltip;
     this._identityIcon.tooltipText = gNavigatorBundle.getString("identity.icon.tooltip");
     this._identityIconLabel.value = icon_label;
     this._identityIconCountryLabel.value = icon_country_label;
@@ -7103,14 +7120,14 @@ var gIdentityHandler = {
 
     // Fill in the CA name if we have a valid TLS certificate.
     if (this._isSecure || this._isCertUserOverridden) {
-      verifier = this._identityBox.tooltipText;
+      verifier = this._identityIconLabels.tooltipText;
     }
 
     // Fill in organization information if we have a valid EV certificate.
     if (this._isEV) {
       let iData = this.getIdentityData();
       host = owner = iData.subjectOrg;
-      verifier = this._identityBox.tooltipText;
+      verifier = this._identityIconLabels.tooltipText;
 
       // Build an appropriate supplemental block out of whatever location data we have
       if (iData.city)
diff --git a/browser/base/content/browser.xul b/browser/base/content/browser.xul
index 283e10ce65a9..85914ec9875d 100644
--- a/browser/base/content/browser.xul
+++ b/browser/base/content/browser.xul
@@ -177,6 +177,7 @@
            orient="vertical"
            ignorekeys="true"
            hidden="true"
+           tabspecific="true"
            onpopupshown="StarUI.panelShown(event);"
            aria-labelledby="editBookmarkPanelTitle">
       <row id="editBookmarkPanelHeader" align="center" hidden="true">
diff --git a/browser/base/content/test/general/browser_utilityOverlay.js b/browser/base/content/test/general/browser_utilityOverlay.js
index 04e0c85a6154..f3a480032897 100644
--- a/browser/base/content/test/general/browser_utilityOverlay.js
+++ b/browser/base/content/test/general/browser_utilityOverlay.js
@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 const gTests = [
+  test_eventMatchesKey,
   test_getTopWin,
   test_getBoolPref,
   test_openNewTabWith,
@@ -25,6 +26,57 @@ function runNextTest() {
   }
 }
 
+function test_eventMatchesKey() {
+  let eventMatchResult;
+  let key;
+  let checkEvent = function(e) {
+    e.stopPropagation();
+    e.preventDefault();
+    eventMatchResult = eventMatchesKey(e, key);
+  }
+  document.addEventListener("keypress", checkEvent);
+
+  try {
+    key = document.createElement("key");
+    let keyset = document.getElementById("mainKeyset");
+    key.setAttribute("key", "t");
+    key.setAttribute("modifiers", "accel");
+    keyset.appendChild(key);
+    EventUtils.synthesizeKey("t", {accelKey: true});
+    is(eventMatchResult, true, "eventMatchesKey: one modifier");
+    keyset.removeChild(key);
+
+    key = document.createElement("key");
+    key.setAttribute("key", "g");
+    key.setAttribute("modifiers", "accel,shift");
+    keyset.appendChild(key);
+    EventUtils.synthesizeKey("g", {accelKey: true, shiftKey: true});
+    is(eventMatchResult, true, "eventMatchesKey: combination modifiers");
+    keyset.removeChild(key);
+
+    key = document.createElement("key");
+    key.setAttribute("key", "w");
+    key.setAttribute("modifiers", "accel");
+    keyset.appendChild(key);
+    EventUtils.synthesizeKey("f", {accelKey: true});
+    is(eventMatchResult, false, "eventMatchesKey: mismatch keys");
+    keyset.removeChild(key);
+
+    key = document.createElement("key");
+    key.setAttribute("keycode", "VK_DELETE");
+    keyset.appendChild(key);
+    EventUtils.synthesizeKey("VK_DELETE", {accelKey: true});
+    is(eventMatchResult, false, "eventMatchesKey: mismatch modifiers");
+    keyset.removeChild(key);
+  } finally {
+    // Make sure to remove the event listener so future tests don't
+    // fail when they simulate key presses.
+    document.removeEventListener("keypress", checkEvent);
+  };
+
+  runNextTest();
+}
+
 function test_getTopWin() {
   is(getTopWin(), window, "got top window");
   runNextTest();
diff --git a/browser/base/content/test/tabPrompts/browser.ini b/browser/base/content/test/tabPrompts/browser.ini
index 187ac7c9b14b..9b94f14c588d 100644
--- a/browser/base/content/test/tabPrompts/browser.ini
+++ b/browser/base/content/test/tabPrompts/browser.ini
@@ -1,3 +1,4 @@
+[browser_closeTabSpecificPanels.js]
 [browser_multiplePrompts.js]
 [browser_openPromptInBackgroundTab.js]
 support-files = openPromptOffTimeout.html
diff --git a/browser/base/content/test/tabPrompts/browser_closeTabSpecificPanels.js b/browser/base/content/test/tabPrompts/browser_closeTabSpecificPanels.js
new file mode 100644
index 000000000000..717350e53186
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_closeTabSpecificPanels.js
@@ -0,0 +1,41 @@
+"use strict";
+
+/*
+ * This test creates multiple panels, one that has been tagged as specific to its tab's content
+ * and one that isn't. When a tab loses focus, panel specific to that tab should close.
+ * The non-specific panel should remain open.
+ *
+ */
+
+add_task(function*() {
+  let tab1 = gBrowser.addTab("http://mochi.test:8888/#0");
+  let tab2 = gBrowser.addTab("http://mochi.test:8888/#1");
+  let specificPanel = document.createElement("panel");
+  specificPanel.setAttribute("tabspecific", "true");
+  let generalPanel = document.createElement("panel");
+  let anchor = document.getElementById(CustomizableUI.AREA_NAVBAR);
+
+  anchor.appendChild(specificPanel);
+  anchor.appendChild(generalPanel);
+  is(specificPanel.state, "closed", "specificPanel starts as closed");
+  is(generalPanel.state, "closed", "generalPanel starts as closed");
+
+  let specificPanelPromise = BrowserTestUtils.waitForEvent(specificPanel, "popupshown");
+  specificPanel.openPopupAtScreen(210, 210);
+  yield specificPanelPromise;
+  is(specificPanel.state, "open", "specificPanel has been opened");
+
+  let generalPanelPromise = BrowserTestUtils.waitForEvent(generalPanel, "popupshown");
+  generalPanel.openPopupAtScreen(510,510);
+  yield generalPanelPromise;
+  is(generalPanel.state, "open", "generalPanel has been opened");
+
+  gBrowser.tabContainer.advanceSelectedTab(-1, true);
+  is(specificPanel.state, "closed", "specificPanel panel is closed after its tab loses focus");
+  is(generalPanel.state, "open", "generalPanel is still open after tab switch");
+
+  specificPanel.remove();
+  generalPanel.remove();
+  gBrowser.removeTab(tab1);
+  gBrowser.removeTab(tab2);
+});
diff --git a/browser/base/content/utilityOverlay.js b/browser/base/content/utilityOverlay.js
index 5c27cf4816c6..2bac7d00b3c3 100644
--- a/browser/base/content/utilityOverlay.js
+++ b/browser/base/content/utilityOverlay.js
@@ -478,6 +478,46 @@ function closeMenus(node)
   }
 }
 
+/** This function takes in a key element and compares it to the keys pressed during an event.
+ *
+ * @param aEvent
+ *        The KeyboardEvent event you want to compare against your key.
+ *
+ * @param aKey
+ *        The <key> element checked to see if it was called in aEvent.
+ *        For example, aKey can be a variable set to document.getElementById("key_close")
+ *        to check if the close command key was pressed in aEvent.
+*/
+function eventMatchesKey(aEvent, aKey)
+{
+  let keyPressed = aKey.getAttribute("key").toLowerCase();
+  let keyModifiers = aKey.getAttribute("modifiers");
+  let modifiers = ["Alt", "Control", "Meta", "Shift"];
+
+  if (aEvent.key != keyPressed) {
+    return false;
+  }
+  let eventModifiers = modifiers.filter(modifier => aEvent.getModifierState(modifier));
+  // Check if aEvent has a modifier and aKey doesn't
+  if (eventModifiers.length > 0 && keyModifiers.length == 0) {
+     return false;
+  }
+  // Check whether aKey's modifiers match aEvent's modifiers
+  if (keyModifiers) {
+    keyModifiers = keyModifiers.split(/[\s,]+/);
+    // Capitalize first letter of aKey's modifers to compare to aEvent's modifier
+    keyModifiers.forEach(function(modifier, index) {
+      if (modifier == "accel") {
+        keyModifiers[index] = AppConstants.platform == "macosx" ?  "Meta" : "Control";
+      } else {
+        keyModifiers[index] = modifier[0].toUpperCase() + modifier.slice(1);
+      }
+    });
+    return modifiers.every(modifier => keyModifiers.includes(modifier) == aEvent.getModifierState(modifier));
+  }
+  return true;
+}
+
 // Gather all descendent text under given document node.
 function gatherTextUnder ( root )
 {
diff --git a/browser/components/customizableui/CustomizableUI.jsm b/browser/components/customizableui/CustomizableUI.jsm
index f62bc5022bb3..3533b316f0a6 100644
--- a/browser/components/customizableui/CustomizableUI.jsm
+++ b/browser/components/customizableui/CustomizableUI.jsm
@@ -1358,6 +1358,9 @@ var CustomizableUIInternal = {
       }
       node.setAttribute("removable", aWidget.removable);
       node.setAttribute("overflows", aWidget.overflows);
+      if (aWidget.tabSpecific) {
+        node.setAttribute("tabspecific", aWidget.tabSpecific);
+      }
       node.setAttribute("label", this.getLocalizedProperty(aWidget, "label"));
       let additionalTooltipArguments = [];
       if (aWidget.shortcutId) {
@@ -2310,6 +2313,7 @@ var CustomizableUIInternal = {
       overflows: true,
       defaultArea: null,
       shortcutId: null,
+      tabSpecific: false,
       tooltiptext: null,
       showInPrivateBrowsing: true,
       _introducedInVersion: -1,
@@ -2340,7 +2344,7 @@ var CustomizableUIInternal = {
       }
     }
 
-    const kOptBoolProps = ["removable", "showInPrivateBrowsing", "overflows"];
+    const kOptBoolProps = ["removable", "showInPrivateBrowsing", "overflows", "tabSpecific"];
     for (let prop of kOptBoolProps) {
       if (typeof aData[prop] == "boolean") {
         widget[prop] = aData[prop];
diff --git a/browser/components/customizableui/content/panelUI.js b/browser/components/customizableui/content/panelUI.js
index cb525dd0246d..15c4c00ab533 100644
--- a/browser/components/customizableui/content/panelUI.js
+++ b/browser/components/customizableui/content/panelUI.js
@@ -335,6 +335,9 @@ const PanelUI = {
       tempPanel.setAttribute("id", "customizationui-widget-panel");
       tempPanel.setAttribute("class", "cui-widget-panel");
       tempPanel.setAttribute("viewId", aViewId);
+      if (aAnchor.getAttribute("tabspecific")) {
+        tempPanel.setAttribute("tabspecific", true);
+      }
       if (this._disableAnimations) {
         tempPanel.setAttribute("animate", "false");
       }
diff --git a/browser/extensions/pocket/bootstrap.js b/browser/extensions/pocket/bootstrap.js
index 6ba39b0e8c50..729686839c00 100644
--- a/browser/extensions/pocket/bootstrap.js
+++ b/browser/extensions/pocket/bootstrap.js
@@ -88,6 +88,7 @@ function CreatePocketWidget(reason) {
     defaultArea: CustomizableUI.AREA_NAVBAR,
     introducedInVersion: "pref",
     type: "view",
+    tabSpecific: true,
     viewId: "PanelUI-pocketView",
     label: gPocketBundle.GetStringFromName("pocket-button.label"),
     tooltiptext: gPocketBundle.GetStringFromName("pocket-button.tooltiptext"),
diff --git a/browser/locales/en-US/chrome/browser/browser.properties b/browser/locales/en-US/chrome/browser/browser.properties
index ca13f28789d4..f35d6ad74e3c 100644
--- a/browser/locales/en-US/chrome/browser/browser.properties
+++ b/browser/locales/en-US/chrome/browser/browser.properties
@@ -330,8 +330,6 @@ identity.identified.verifier=Verified by: %S
 identity.identified.verified_by_you=You have added a security exception for this site.
 identity.identified.state_and_country=%S, %S
 
-identity.unknown.tooltip=This website does not supply identity information.
-
 identity.icon.tooltip=Show site information
 
 trackingProtection.intro.title=How Tracking Protection works
diff --git a/devtools/client/shared/components/reps/document.js b/devtools/client/shared/components/reps/document.js
index 525d2bbd9382..3ddef9b84b63 100644
--- a/devtools/client/shared/components/reps/document.js
+++ b/devtools/client/shared/components/reps/document.js
@@ -11,7 +11,7 @@ define(function (require, exports, module) {
   const React = require("devtools/client/shared/vendor/react");
 
   // Reps
-  const { isGrip, getFileName } = require("./rep-utils");
+  const { isGrip, getURLDisplayString } = require("./rep-utils");
 
   // Shortcuts
   const { span } = React.DOM;
@@ -28,7 +28,7 @@ define(function (require, exports, module) {
 
     getLocation: function (grip) {
       let location = grip.preview.location;
-      return location ? getFileName(location) : "";
+      return location ? getURLDisplayString(location) : "";
     },
 
     getTitle: function (grip) {
diff --git a/devtools/client/shared/components/reps/object-with-url.js b/devtools/client/shared/components/reps/object-with-url.js
index a52f5f0da635..9106527f2fa9 100644
--- a/devtools/client/shared/components/reps/object-with-url.js
+++ b/devtools/client/shared/components/reps/object-with-url.js
@@ -11,7 +11,7 @@ define(function (require, exports, module) {
   const React = require("devtools/client/shared/vendor/react");
 
   // Reps
-  const { isGrip } = require("./rep-utils");
+  const { isGrip, getURLDisplayString } = require("./rep-utils");
 
   // Shortcuts
   const { span } = React.DOM;
@@ -42,7 +42,7 @@ define(function (require, exports, module) {
     },
 
     getDescription: function (grip) {
-      return grip.preview.url;
+      return getURLDisplayString(grip.preview.url);
     },
 
     render: function () {
diff --git a/devtools/client/shared/components/reps/rep-utils.js b/devtools/client/shared/components/reps/rep-utils.js
index be8f5bb2568d..60d6706c1136 100644
--- a/devtools/client/shared/components/reps/rep-utils.js
+++ b/devtools/client/shared/components/reps/rep-utils.js
@@ -109,6 +109,10 @@ define(function (require, exports, module) {
     return {};
   }
 
+  function getURLDisplayString(url) {
+    return cropString(url);
+  }
+
   function isDataURL(url) {
     return (url && url.substr(0, 5) == "data:");
   }
@@ -147,4 +151,5 @@ define(function (require, exports, module) {
   exports.parseURLParams = parseURLParams;
   exports.parseURLEncodedText = parseURLEncodedText;
   exports.getFileName = getFileName;
+  exports.getURLDisplayString = getURLDisplayString;
 });
diff --git a/devtools/client/shared/components/reps/stylesheet.js b/devtools/client/shared/components/reps/stylesheet.js
index 35e3bb162166..c1fc7f1be219 100644
--- a/devtools/client/shared/components/reps/stylesheet.js
+++ b/devtools/client/shared/components/reps/stylesheet.js
@@ -11,7 +11,7 @@ define(function (require, exports, module) {
   const React = require("devtools/client/shared/vendor/react");
 
   // Reps
-  const { isGrip, getFileName } = require("./rep-utils");
+  const { isGrip, getURLDisplayString } = require("./rep-utils");
 
   // Shortcuts
   const DOM = React.DOM;
@@ -41,7 +41,7 @@ define(function (require, exports, module) {
     getLocation: function (grip) {
       // Embedded stylesheets don't have URL and so, no preview.
       let url = grip.preview ? grip.preview.url : "";
-      return url ? getFileName(url) : "";
+      return url ? getURLDisplayString(url) : "";
     },
 
     render: function () {
diff --git a/devtools/client/shared/components/reps/window.js b/devtools/client/shared/components/reps/window.js
index 182936bb9e16..13bae89f5bca 100644
--- a/devtools/client/shared/components/reps/window.js
+++ b/devtools/client/shared/components/reps/window.js
@@ -11,7 +11,7 @@ define(function (require, exports, module) {
   const React = require("devtools/client/shared/vendor/react");
 
   // Reps
-  const { isGrip, cropString } = require("./rep-utils");
+  const { isGrip, getURLDisplayString } = require("./rep-utils");
 
   // Shortcuts
   const DOM = React.DOM;
@@ -38,7 +38,7 @@ define(function (require, exports, module) {
     },
 
     getLocation: function (grip) {
-      return cropString(grip.preview.url);
+      return getURLDisplayString(grip.preview.url);
     },
 
     render: function () {
diff --git a/devtools/client/shared/components/test/mochitest/test_reps_document.html b/devtools/client/shared/components/test/mochitest/test_reps_document.html
index bd993cff7805..f72d076a8fed 100644
--- a/devtools/client/shared/components/test/mochitest/test_reps_document.html
+++ b/devtools/client/shared/components/test/mochitest/test_reps_document.html
@@ -41,7 +41,7 @@ window.onload = Task.async(function* () {
 
     // Test rendering
     const renderedComponent = renderComponent(Document.rep, { object: gripStub });
-    is(renderedComponent.textContent, "/en-US/firefox/new/", "Document rep has expected text content");
+    is(renderedComponent.textContent, "https://www.mozilla.org/en-US/firefox/new/", "Document rep has expected text content");
   } catch(e) {
     ok(false, "Got an error: " + DevToolsUtils.safeErrorString(e));
   } finally {
diff --git a/devtools/client/shared/components/test/mochitest/test_reps_stylesheet.html b/devtools/client/shared/components/test/mochitest/test_reps_stylesheet.html
index bdd4cb973aac..acca49bee0a5 100644
--- a/devtools/client/shared/components/test/mochitest/test_reps_stylesheet.html
+++ b/devtools/client/shared/components/test/mochitest/test_reps_stylesheet.html
@@ -39,7 +39,7 @@ window.onload = Task.async(function* () {
 
     // Test rendering
     const renderedComponent = renderComponent(StyleSheet.rep, { object: gripStub });
-    is(renderedComponent.textContent, "StyleSheet styles.css", "StyleSheet rep has expected text content");
+    is(renderedComponent.textContent, "StyleSheet https://example.com/styles.css", "StyleSheet rep has expected text content");
   } catch(e) {
     ok(false, "Got an error: " + DevToolsUtils.safeErrorString(e));
   } finally {
diff --git a/devtools/client/themes/memory.css b/devtools/client/themes/memory.css
index c504f912ba89..328cde44b84d 100644
--- a/devtools/client/themes/memory.css
+++ b/devtools/client/themes/memory.css
@@ -436,7 +436,8 @@ html, body, #app, #memory-tool {
    * These subcolumns may have specific widths or need to flex.
    */
   display: flex;
-  text-align: end;
+  /* Make sure units/decimals/... are always vertically aligned to right in both LTR and RTL locales */
+  text-align: right;
   border-inline-end: var(--cell-border-color) 1px solid;
 }
 
@@ -486,7 +487,11 @@ html, body, #app, #memory-tool {
 }
 
 .heap-tree-number {
-  padding-inline-start: 3px;
+  padding: 0 3px;
+  flex: 1;
+  color: var(--theme-content-color3);
+  /* Make sure number doesn't appear backwards on RTL locales */
+  direction: ltr;
 }
 
 .heap-tree-percent {
@@ -499,11 +504,6 @@ html, body, #app, #memory-tool {
   font-family: var(--monospace-font-family);
 }
 
-.heap-tree-number {
-  flex: 1;
-  color: var(--theme-content-color3);
-}
-
 .heap-tree-percent {
   width: 4ch;
 }
diff --git a/toolkit/modules/Finder.jsm b/toolkit/modules/Finder.jsm
index b6e705e4a8e6..0563f3164f1a 100644
--- a/toolkit/modules/Finder.jsm
+++ b/toolkit/modules/Finder.jsm
@@ -31,6 +31,7 @@ function Finder(docShell) {
   this._fastFind = Cc["@mozilla.org/typeaheadfind;1"].createInstance(Ci.nsITypeAheadFind);
   this._fastFind.init(docShell);
 
+  this._currentFoundRange = null;
   this._docShell = docShell;
   this._listeners = [];
   this._previousLink = null;
@@ -40,6 +41,8 @@ function Finder(docShell) {
   docShell.QueryInterface(Ci.nsIInterfaceRequestor)
           .getInterface(Ci.nsIWebProgress)
           .addProgressListener(this, Ci.nsIWebProgress.NOTIFY_LOCATION);
+  BrowserUtils.getRootWindow(this._docShell).addEventListener("unload",
+    this.onLocationChange.bind(this, { isTopLevel: true }));
 }
 
 Finder.prototype = {
@@ -62,7 +65,8 @@ Finder.prototype = {
       .getInterface(Ci.nsIWebProgress)
       .removeProgressListener(this, Ci.nsIWebProgress.NOTIFY_LOCATION);
     this._listeners = [];
-    this._fastFind = this._docShell = this._previousLink = this._highlighter = null;
+    this._currentFoundRange = this._fastFind = this._docShell = this._previousLink =
+      this._highlighter = null;
   },
 
   addResultListener: function (aListener) {
@@ -139,11 +143,15 @@ Finder.prototype = {
   },
 
   set caseSensitive(aSensitive) {
+    if (this._fastFind.caseSensitive === aSensitive)
+      return;
     this._fastFind.caseSensitive = aSensitive;
     this.iterator.reset();
   },
 
   set entireWord(aEntireWord) {
+    if (this._fastFind.entireWord === aEntireWord)
+      return;
     this._fastFind.entireWord = aEntireWord;
     this.iterator.reset();
   },
@@ -335,6 +343,8 @@ Finder.prototype = {
   },
 
   onHighlightAllChange(highlightAll) {
+    if (this._iterator)
+      this._iterator.reset();
     if (this._highlighter)
       this._highlighter.onHighlightAllChange(highlightAll);
   },
@@ -379,12 +389,21 @@ Finder.prototype = {
     }
   },
 
-  _notifyMatchesCount: function(result) {
+  _notifyMatchesCount: function(result = this._currentMatchesCountResult) {
+    if (!result)
+      return;
+    // The `_currentFound` property is only used for internal bookkeeping.
+    delete result._currentFound;
+    if (result.total == this._currentMatchLimit)
+      result.total = -1;
+
     for (let l of this._listeners) {
       try {
         l.onMatchesCountResult(result);
       } catch (ex) {}
     }
+
+    this._currentMatchesCountResult = null;
   },
 
   requestMatchesCount: function(aWord, aMatchLimit, aLinksOnly) {
@@ -398,12 +417,14 @@ Finder.prototype = {
     }
 
     let window = this._getWindow();
-    let result = {
+    this._currentFoundRange = this._fastFind.getFoundRange();
+    this._currentMatchLimit = aMatchLimit;
+
+    this._currentMatchesCountResult = {
       total: 0,
       current: 0,
       _currentFound: false
     };
-    let foundRange = this._fastFind.getFoundRange();
 
     this.iterator.start({
       caseSensitive: this._fastFind.caseSensitive,
@@ -411,30 +432,38 @@ Finder.prototype = {
       finder: this,
       limit: aMatchLimit,
       linksOnly: aLinksOnly,
-      onRange: range => {
-        ++result.total;
-        if (!result._currentFound) {
-          ++result.current;
-          result._currentFound = (foundRange &&
-            range.startContainer == foundRange.startContainer &&
-            range.startOffset == foundRange.startOffset &&
-            range.endContainer == foundRange.endContainer &&
-            range.endOffset == foundRange.endOffset);
-        }
-      },
+      listener: this,
       useCache: true,
       word: aWord
-    }).then(() => {
-      // The `_currentFound` property is only used for internal bookkeeping.
-      delete result._currentFound;
-
-      if (result.total == aMatchLimit)
-        result.total = -1;
-
-      this._notifyMatchesCount(result);
-    });
+    }).then(this._notifyMatchesCount.bind(this));
   },
 
+  // FinderIterator listener implementation
+
+  onIteratorRangeFound(range) {
+    let result = this._currentMatchesCountResult;
+    if (!result)
+      return;
+
+    ++result.total;
+    if (!result._currentFound) {
+      ++result.current;
+      result._currentFound = (this._currentFoundRange &&
+        range.startContainer == this._currentFoundRange.startContainer &&
+        range.startOffset == this._currentFoundRange.startOffset &&
+        range.endContainer == this._currentFoundRange.endContainer &&
+        range.endOffset == this._currentFoundRange.endOffset);
+    }
+  },
+
+  onIteratorReset() {},
+
+  onIteratorRestart({ word, linksOnly }) {
+    this.requestMatchesCount(word, this._currentMatchLimit, linksOnly);
+   },
+
+   onIteratorStart() {},
+
   _getWindow: function () {
     return this._docShell.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindow);
   },
@@ -555,7 +584,7 @@ Finder.prototype = {
       return;
 
     // Avoid leaking if we change the page.
-    this._previousLink = null;
+    this._previousLink = this._currentFoundRange = null;
     this.highlighter.onLocationChange();
     this.iterator.reset();
   },
diff --git a/toolkit/modules/FinderHighlighter.jsm b/toolkit/modules/FinderHighlighter.jsm
index c4f923b8e918..df051ea60772 100644
--- a/toolkit/modules/FinderHighlighter.jsm
+++ b/toolkit/modules/FinderHighlighter.jsm
@@ -18,6 +18,7 @@ XPCOMUtils.defineLazyGetter(this, "kDebug", () => {
   return Services.prefs.getPrefType(kDebugPref) && Services.prefs.getBoolPref(kDebugPref);
 });
 
+const kContentChangeThresholdPx = 5;
 const kModalHighlightRepaintFreqMs = 10;
 const kHighlightAllPref = "findbar.highlightAll";
 const kModalHighlightPref = "findbar.modalHighlight";
@@ -153,6 +154,7 @@ function FinderHighlighter(finder) {
   this._currentFoundRange = null;
   this._modal = Services.prefs.getBoolPref(kModalHighlightPref);
   this._highlightAll = Services.prefs.getBoolPref(kHighlightAllPref);
+  this._lastIteratorParams = null;
   this.finder = finder;
   this.visible = false;
 }
@@ -207,56 +209,72 @@ FinderHighlighter.prototype = {
     let window = this.finder._getWindow();
     let controller = this.finder._getSelectionController(window);
     let doc = window.document;
-    let found = false;
-
-    this.clear();
+    this._found = false;
 
     if (!controller || !doc || !doc.documentElement) {
       // Without the selection controller,
       // we are unable to (un)highlight any matches
-      return found;
+      return this._found;
     }
 
     if (highlight) {
-      yield this.iterator.start({
+      let params = {
         caseSensitive: this.finder._fastFind.caseSensitive,
         entireWord: this.finder._fastFind.entireWord,
         linksOnly, word,
         finder: this.finder,
-        onRange: range => {
-          this.highlightRange(range, controller, window);
-          found = true;
-        },
+        listener: this,
         useCache: true
-      });
-      if (found)
-        this.finder._outlineLink(true);
+      };
+      if (this.iterator._areParamsEqual(params, this._lastIteratorParams))
+        return this._found;
+      if (params) {
+        yield this.iterator.start(params);
+        if (this._found)
+          this.finder._outlineLink(true);
+      }
     } else {
       this.hide(window);
-      this.clear();
-      this.iterator.reset();
 
       // Removing the highlighting always succeeds, so return true.
-      found = true;
+      this._found = true;
     }
 
-    return found;
+    return this._found;
   }),
 
+  // FinderIterator listener implementation
+
+  onIteratorRangeFound(range) {
+    this.highlightRange(range);
+    this._found = true;
+  },
+
+  onIteratorReset() {
+    this.clear();
+  },
+
+  onIteratorRestart() {},
+
+  onIteratorStart(params) {
+    // Save a clean params set for use later in the `update()` method.
+    this._lastIteratorParams = params;
+    this.clear();
+    if (!this._modal)
+      this.hide(this.finder._getWindow(), this.finder._fastFind.getFoundRange());
+  },
+
   /**
    * Add a range to the find selection, i.e. highlight it, and if it's inside an
    * editable node, track it.
    *
-   * @param {nsIDOMRange}            range      Range object to be highlighted
-   * @param {nsISelectionController} controller Selection controller of the
-   *                                            document that the range belongs
-   *                                            to
-   * @param {nsIDOMWindow}           window     Window object, whose DOM tree
-   *                                            is being traversed
+   * @param {nsIDOMRange} range Range object to be highlighted
    */
-  highlightRange(range, controller, window) {
+  highlightRange(range) {
     let node = range.startContainer;
     let editableNode = this._getEditableNode(node);
+    let window = node.ownerDocument.defaultView;
+    let controller = this.finder._getSelectionController(window);
     if (editableNode) {
       controller = editableNode.editor.selectionController;
     }
@@ -325,8 +343,11 @@ FinderHighlighter.prototype = {
       }
     }
 
-    if (!this._modal || !this.visible)
-      return;
+    if (this._modalRepaintScheduler) {
+      window.clearTimeout(this._modalRepaintScheduler);
+      this._modalRepaintScheduler = null;
+    }
+    this._lastWindowDimensions = null;
 
     if (this._modalHighlightOutline)
       this._modalHighlightOutline.setAttributeForElement(kModalOutlineId, "hidden", "true");
@@ -364,15 +385,12 @@ FinderHighlighter.prototype = {
     let foundRange = this.finder._fastFind.getFoundRange();
     if (!this._modal) {
       if (this._highlightAll) {
+        this._currentFoundRange = foundRange;
         let params = this.iterator.params;
-        if (this._lastIteratorParams &&
-            this.iterator._areParamsEqual(params, this._lastIteratorParams)) {
+        if (this.iterator._areParamsEqual(params, this._lastIteratorParams))
           return;
-        }
-        this.hide(window, foundRange);
-        if (params.word)
+        if (params)
           this.highlight(true, params.word, params.linksOnly);
-        this._lastIteratorParams = params;
       }
       return;
     }
@@ -436,8 +454,7 @@ FinderHighlighter.prototype = {
    * keep to build the mask for.
    */
   clear() {
-    if (!this._modal)
-      return;
+    this._currentFoundRange = null;
 
     // Reset the Map, because no range references a node anymore.
     if (this._modalHighlightRectsMap)
@@ -451,6 +468,8 @@ FinderHighlighter.prototype = {
    * everything when the user starts to find in page again.
    */
   onLocationChange() {
+    this.clear();
+
     if (!this._modalHighlightOutline)
       return;
 
@@ -740,13 +759,14 @@ FinderHighlighter.prototype = {
 
     // Make sure the dimmed mask node takes the full width and height that's available.
     let {width, height} = this._getWindowDimensions(window);
+    this._lastWindowDimensions = { width, height };
     maskNode.setAttribute("id", kMaskId);
     maskNode.setAttribute("class", kMaskId + (kDebug ? ` ${kModalIdPrefix}-findbar-debug` : ""));
     maskNode.setAttribute("style", `width: ${width}px; height: ${height}px;`);
     if (this._brightText)
       maskNode.setAttribute("brighttext", "true");
 
-    if (paintContent) {
+    if (paintContent || this._modalHighlightAllMask) {
       // Create a DOM node for each rectangle representing the ranges we found.
       let maskContent = [];
       const kRectClassName = kModalIdPrefix + "-findbar-modalHighlight-rect";
@@ -794,12 +814,39 @@ FinderHighlighter.prototype = {
    * `kModalHighlightRepaintFreqMs` milliseconds.
    *
    * @param {nsIDOMWindow} window
+   * @param {Boolean}      contentChanged Whether the documents' content changed
+   *                                      in the meantime. This happens when the
+   *                                      DOM is updated whilst the page is loaded.
    */
-  _scheduleRepaintOfMask(window) {
-    if (this._modalRepaintScheduler)
+  _scheduleRepaintOfMask(window, contentChanged = false) {
+    if (this._modalRepaintScheduler) {
       window.clearTimeout(this._modalRepaintScheduler);
-    this._modalRepaintScheduler = window.setTimeout(
-      this._repaintHighlightAllMask.bind(this, window), kModalHighlightRepaintFreqMs);
+      this._modalRepaintScheduler = null;
+    }
+
+    // When we request to repaint unconditionally, we mean to call
+    // `_repaintHighlightAllMask()` right after the timeout.
+    if (!this._unconditionalRepaintRequested)
+      this._unconditionalRepaintRequested = !contentChanged;
+
+    this._modalRepaintScheduler = window.setTimeout(() => {
+      if (this._unconditionalRepaintRequested) {
+        this._unconditionalRepaintRequested = false;
+        this._repaintHighlightAllMask(window);
+        return;
+      }
+
+      let { width, height } = this._getWindowDimensions(window);
+      if (!this._modalHighlightRectsMap ||
+          (Math.abs(this._lastWindowDimensions.width - width) < kContentChangeThresholdPx &&
+           Math.abs(this._lastWindowDimensions.height - height) < kContentChangeThresholdPx)) {
+        return;
+      }
+
+      this.iterator.restart(this.finder);
+      this._lastWindowDimensions = { width, height };
+      this._repaintHighlightAllMask(window);
+    }, kModalHighlightRepaintFreqMs);
   },
 
   /**
@@ -838,12 +885,12 @@ FinderHighlighter.prototype = {
       return;
 
     this._highlightListeners = [
-      this._scheduleRepaintOfMask.bind(this, window),
+      this._scheduleRepaintOfMask.bind(this, window, true),
       this.hide.bind(this, window, null)
     ];
-    window.addEventListener("DOMContentLoaded", this._highlightListeners[0]);
+    let target = this.iterator._getDocShell(window).chromeEventHandler;
+    target.addEventListener("MozAfterPaint", this._highlightListeners[0]);
     window.addEventListener("click", this._highlightListeners[1]);
-    window.addEventListener("resize", this._highlightListeners[1]);
   },
 
   /**
@@ -855,9 +902,9 @@ FinderHighlighter.prototype = {
     if (!this._highlightListeners)
       return;
 
-    window.removeEventListener("DOMContentLoaded", this._highlightListeners[0]);
+    let target = this.iterator._getDocShell(window).chromeEventHandler;
+    target.removeEventListener("MozAfterPaint", this._highlightListeners[0]);
     window.removeEventListener("click", this._highlightListeners[1]);
-    window.removeEventListener("resize", this._highlightListeners[1]);
 
     this._highlightListeners = null;
   },
diff --git a/toolkit/modules/FinderIterator.jsm b/toolkit/modules/FinderIterator.jsm
index 84d76c22f108..871417e0712d 100644
--- a/toolkit/modules/FinderIterator.jsm
+++ b/toolkit/modules/FinderIterator.jsm
@@ -30,6 +30,8 @@ this.FinderIterator = {
   get kIterationSizeMax() { return kIterationSizeMax },
 
   get params() {
+    if (!this._currentParams && !this._previousParams)
+      return null;
     return Object.assign({}, this._currentParams || this._previousParams);
   },
 
@@ -42,9 +44,9 @@ this.FinderIterator = {
    * yield `undefined`, instead of a range.
    * Upon re-entrance after a break, we check if `stop()` was called during the
    * break and if so, we stop iterating.
-   * Results are also passed to the `onRange` callback method, along with a flag
-   * that specifies if the result comes from the cache or is fresh. The callback
-   * also adheres to the `limit` flag.
+   * Results are also passed to the `listener.onIteratorRangeFound` callback
+   * method, along with a flag that specifies if the result comes from the cache
+   * or is fresh. The callback also adheres to the `limit` flag.
    * The returned promise is resolved when 1) the limit is reached, 2) when all
    * the ranges have been found or 3) when `stop()` is called whilst iterating.
    *
@@ -58,14 +60,19 @@ this.FinderIterator = {
    * @param {Boolean}  [options.linksOnly]   Only yield ranges that are inside a
    *                                         hyperlink (used by QuickFind).
    *                                         Optional, defaults to `false`.
-   * @param {Function} options.onRange       Callback invoked when a range is found
+   * @param {Object}   options.listener    Listener object that implements the
+   *                                       following callback functions:
+   *                                        - onIteratorRangeFound({nsIDOMRange} range);
+   *                                        - onIteratorReset();
+   *                                        - onIteratorRestart({Object} iterParams);
+   *                                        - onIteratorStart({Object} iterParams);
    * @param {Boolean}  [options.useCache]    Whether to allow results already
    *                                         present in the cache or demand fresh.
    *                                         Optional, defaults to `false`.
    * @param {String}   options.word          Word to search for
    * @return {Promise}
    */
-  start({ caseSensitive, entireWord, finder, limit, linksOnly, onRange, useCache, word }) {
+  start({ caseSensitive, entireWord, finder, limit, linksOnly, listener, useCache, word }) {
     // Take care of default values for non-required options.
     if (typeof limit != "number")
       limit = -1;
@@ -83,23 +90,27 @@ this.FinderIterator = {
       throw new Error("Missing required option 'finder'");
     if (!word)
       throw new Error("Missing required option 'word'");
-    if (typeof onRange != "function")
-      throw new TypeError("Missing valid, required option 'onRange'");
+    if (typeof listener != "object" || !listener.onIteratorRangeFound)
+      throw new TypeError("Missing valid, required option 'listener'");
 
-    // Don't add the same listener twice.
-    if (this._listeners.has(onRange))
-      throw new Error("Already listening to iterator results");
+    // If the listener was added before, make sure the promise is resolved before
+    // we replace it with another.
+    if (this._listeners.has(listener)) {
+      let { onEnd } = this._listeners.get(listener);
+      if (onEnd)
+        onEnd();
+    }
 
     let window = finder._getWindow();
     let resolver;
     let promise = new Promise(resolve => resolver = resolve);
     let iterParams = { caseSensitive, entireWord, linksOnly, useCache, word };
 
-    this._listeners.set(onRange, { limit, onEnd: resolver });
+    this._listeners.set(listener, { limit, onEnd: resolver });
 
     // If we're not running anymore and we're requesting the previous result, use it.
     if (!this.running && this._previousResultAvailable(iterParams)) {
-      this._yieldPreviousResult(onRange, window);
+      this._yieldPreviousResult(listener, window);
       return promise;
     }
 
@@ -110,7 +121,7 @@ this.FinderIterator = {
         throw new Error(`We're currently iterating over '${this._currentParams.word}', not '${word}'`);
 
       // if we're still running, yield the set we have built up this far.
-      this._yieldIntermediateResult(onRange, window);
+      this._yieldIntermediateResult(listener, window);
 
       return promise;
     }
@@ -149,7 +160,27 @@ this.FinderIterator = {
 
     for (let [, { onEnd }] of this._listeners)
       onEnd();
-    this._listeners.clear();
+  },
+
+  /**
+   * Stops the iteration that currently running, if it is, and start a new one
+   * with the exact same params as before.
+   *
+   * @param {Finder} finder Currently active Finder instance
+   */
+  restart(finder) {
+    // Capture current iterator params before we stop the show.
+    let iterParams = this.params;
+    if (!iterParams)
+      return;
+    this.stop();
+
+    // Restart manually.
+    this.running = true;
+    this._currentParams = iterParams;
+
+    this._findAllRanges(finder, finder._getWindow(), ++this._spawnId);
+    this._notifyListeners("restart", iterParams);
   },
 
   /**
@@ -165,6 +196,7 @@ this.FinderIterator = {
     this.ranges = [];
     this.running = false;
 
+    this._notifyListeners("reset");
     for (let [, { onEnd }] of this._listeners)
       onEnd();
     this._listeners.clear();
@@ -191,13 +223,33 @@ this.FinderIterator = {
       this._currentParams.word == word);
   },
 
+  /**
+   * Safely notify all registered listeners that an event has occurred.
+   *
+   * @param {String}   callback    Name of the callback to invoke
+   * @param {mixed}    [params]    Optional argument that will be passed to the
+   *                               callback
+   * @param {Iterable} [listeners] Set of listeners to notify. Optional, defaults
+   *                               to `this._listeners.keys()`.
+   */
+  _notifyListeners(callback, params, listeners = this._listeners.keys()) {
+    callback = "onIterator" + callback.charAt(0).toUpperCase() + callback.substr(1);
+    for (let listener of listeners) {
+      try {
+        listener[callback](params);
+      } catch (ex) {
+        Cu.reportError("FinderIterator Error: " + ex);
+      }
+    }
+  },
+
   /**
    * Internal; check if an iteration request is available in the previous result
    * that we cached.
    *
-   * @param {Boolean}  options.caseSensitive Whether to search in case sensitive
+   * @param  {Boolean} options.caseSensitive Whether to search in case sensitive
    *                                         mode
-   * @param {Boolean}  options.entireWord    Whether to search in entire-word mode
+   * @param  {Boolean} options.entireWord    Whether to search in entire-word mode
    * @param  {Boolean} options.linksOnly     Whether to search for the word to be
    *                                         present in links only
    * @param  {Boolean} options.useCache      Whether the consumer wants to use the
@@ -233,17 +285,20 @@ this.FinderIterator = {
    * make sure we don't block the host process too long. In the case of a break
    * like this, we yield `undefined`, instead of a range.
    *
-   * @param {Function}     onRange     Callback invoked when a range is found
+   * @param {Object}       listener    Listener object
    * @param {Array}        rangeSource Set of ranges to iterate over
    * @param {nsIDOMWindow} window      The window object is only really used
    *                                   for access to `setTimeout`
+   * @param {Boolean}      [withPause] Whether to pause after each `kIterationSizeMax`
+   *                                   number of ranges yielded. Optional, defaults
+   *                                   to `true`.
    * @yield {nsIDOMRange}
    */
-  _yieldResult: function* (onRange, rangeSource, window) {
+  _yieldResult: function* (listener, rangeSource, window, withPause = true) {
     // We keep track of the number of iterations to allow a short pause between
     // every `kIterationSizeMax` number of iterations.
     let iterCount = 0;
-    let { limit, onEnd } = this._listeners.get(onRange);
+    let { limit, onEnd } = this._listeners.get(listener);
     let ranges = rangeSource.slice(0, limit > -1 ? limit : undefined);
     for (let range of ranges) {
       try {
@@ -256,13 +311,13 @@ this.FinderIterator = {
 
       // Pass a flag that is `true` when we're returning the result from a
       // cached previous iteration.
-      onRange(range, !this.running);
+      listener.onIteratorRangeFound(range, !this.running);
       yield range;
 
-      if (++iterCount >= kIterationSizeMax) {
+      if (withPause && ++iterCount >= kIterationSizeMax) {
         iterCount = 0;
         // Make sure to save the current limit for later.
-        this._listeners.set(onRange, { limit, onEnd });
+        this._listeners.set(listener, { limit, onEnd });
         // Sleep for the rest of this cycle.
         yield new Promise(resolve => window.setTimeout(resolve, 0));
         // After a sleep, the set of ranges may have updated.
@@ -271,14 +326,14 @@ this.FinderIterator = {
 
       if (limit !== -1 && --limit === 0) {
         // We've reached our limit; no need to do more work.
-        this._listeners.delete(onRange);
+        this._listeners.delete(listener);
         onEnd();
         return;
       }
     }
 
     // Save the updated limit globally.
-    this._listeners.set(onRange, { limit, onEnd });
+    this._listeners.set(listener, { limit, onEnd });
   },
 
   /**
@@ -286,20 +341,19 @@ this.FinderIterator = {
    * mark the listener as 'catching up', meaning it will not receive fresh
    * results from a running iterator.
    *
-   * @param {Function}     onRange Callback invoked when a range is found
-   * @param {nsIDOMWindow} window  The window object is only really used
-   *                               for access to `setTimeout`
+   * @param {Object}       listener Listener object
+   * @param {nsIDOMWindow} window   The window object is only really used
+   *                                for access to `setTimeout`
    * @yield {nsIDOMRange}
    */
-  _yieldPreviousResult: Task.async(function* (onRange, window) {
-    this._catchingUp.add(onRange);
-    yield* this._yieldResult(onRange, this._previousRanges, window);
-    this._catchingUp.delete(onRange);
-    let { onEnd } = this._listeners.get(onRange);
-    if (onEnd) {
+  _yieldPreviousResult: Task.async(function* (listener, window) {
+    this._notifyListeners("start", this.params, [listener]);
+    this._catchingUp.add(listener);
+    yield* this._yieldResult(listener, this._previousRanges, window);
+    this._catchingUp.delete(listener);
+    let { onEnd } = this._listeners.get(listener);
+    if (onEnd)
       onEnd();
-      this._listeners.delete(onRange);
-    }
   }),
 
   /**
@@ -307,15 +361,16 @@ this.FinderIterator = {
    * mark the listener as 'catching up', meaning it will not receive fresh
    * results from the running iterator.
    *
-   * @param {Function}     onRange Callback invoked when a range is found
-   * @param {nsIDOMWindow} window  The window object is only really used
-   *                               for access to `setTimeout`
+   * @param {Object}       listener Listener object
+   * @param {nsIDOMWindow} window   The window object is only really used
+   *                                for access to `setTimeout`
    * @yield {nsIDOMRange}
    */
-  _yieldIntermediateResult: Task.async(function* (onRange, window) {
-    this._catchingUp.add(onRange);
-    yield* this._yieldResult(onRange, this.ranges, window);
-    this._catchingUp.delete(onRange);
+  _yieldIntermediateResult: Task.async(function* (listener, window) {
+    this._notifyListeners("start", this.params, [listener]);
+    this._catchingUp.add(listener);
+    yield* this._yieldResult(listener, this.ranges, window, false);
+    this._catchingUp.delete(listener);
   }),
 
   /**
@@ -329,6 +384,8 @@ this.FinderIterator = {
    * @yield {nsIDOMRange}
    */
   _findAllRanges: Task.async(function* (finder, window, spawnId) {
+    this._notifyListeners("start", this.params);
+
     // First we collect all frames we need to search through, whilst making sure
     // that the parent window gets dibs.
     let frames = [window].concat(this._collectFrames(window, finder));
@@ -348,21 +405,21 @@ this.FinderIterator = {
         this.ranges.push(range);
 
         // Call each listener with the range we just found.
-        for (let [onRange, { limit, onEnd }] of this._listeners) {
-          if (this._catchingUp.has(onRange))
+        for (let [listener, { limit, onEnd }] of this._listeners) {
+          if (this._catchingUp.has(listener))
             continue;
 
-          onRange(range);
+          listener.onIteratorRangeFound(range);
 
           if (limit !== -1 && --limit === 0) {
             // We've reached our limit; no need to do more work for this listener.
-            this._listeners.delete(onRange);
+            this._listeners.delete(listener);
             onEnd();
             continue;
           }
 
           // Save the updated limit globally.
-          this._listeners.set(onRange, { limit, onEnd });
+          this._listeners.set(listener, { limit, onEnd });
         }
 
         yield range;
diff --git a/toolkit/modules/RemoteFinder.jsm b/toolkit/modules/RemoteFinder.jsm
index 36ca2a23cd31..bdf9c86ad865 100644
--- a/toolkit/modules/RemoteFinder.jsm
+++ b/toolkit/modules/RemoteFinder.jsm
@@ -227,6 +227,7 @@ function RemoteFinderListener(global) {
   for (let msg of this.MESSAGES) {
     global.addMessageListener(msg, this);
   }
+  global.addEventListener("unload", this.destroy.bind(this));
 }
 
 RemoteFinderListener.prototype = {
@@ -250,6 +251,13 @@ RemoteFinderListener.prototype = {
     "Finder:ModalHighlightChange"
   ],
 
+  destroy() {
+    this._finder.destroy();
+    for (let msg of this.MESSAGES)
+      this._global.removeMessageListener(msg, this);
+    this._finder = this._global = null;
+  },
+
   onFindResult: function (aData) {
     this._global.sendAsyncMessage("Finder:Result", aData);
   },
diff --git a/toolkit/modules/tests/browser/browser_FinderHighlighter.js b/toolkit/modules/tests/browser/browser_FinderHighlighter.js
index 1afa9ff474c7..eda6711731ef 100644
--- a/toolkit/modules/tests/browser/browser_FinderHighlighter.js
+++ b/toolkit/modules/tests/browser/browser_FinderHighlighter.js
@@ -145,17 +145,17 @@ add_task(function* testModalResults() {
     }],
     ["ro", {
       rectCount: 41,
-      insertCalls: [1, 2],
-      removeCalls: [1, 2]
+      insertCalls: [1, 4],
+      removeCalls: [1, 3]
     }],
     ["new", {
       rectCount: 2,
-      insertCalls: [1, 2],
-      removeCalls: [1, 2]
+      insertCalls: [1, 4],
+      removeCalls: [1, 3]
     }],
     ["o", {
       rectCount: 492,
-      insertCalls: [1, 2],
+      insertCalls: [1, 3],
       removeCalls: [1, 2]
     }]
   ]);
@@ -293,7 +293,7 @@ add_task(function* testHighlightAllToggle() {
     // to flip the pref.
     expectedResult = {
       rectCount: 0,
-      insertCalls: [1, 1],
+      insertCalls: [0, 1],
       removeCalls: [1, 1]
     };
     promise = promiseTestHighlighterOutput(browser, word, expectedResult);
diff --git a/toolkit/modules/tests/xpcshell/test_FinderIterator.js b/toolkit/modules/tests/xpcshell/test_FinderIterator.js
index 6200b041fdd1..f550e7b91e6e 100644
--- a/toolkit/modules/tests/xpcshell/test_FinderIterator.js
+++ b/toolkit/modules/tests/xpcshell/test_FinderIterator.js
@@ -45,9 +45,11 @@ add_task(function* test_start() {
     caseSensitive: false,
     entireWord: false,
     finder: gMockFinder,
-    onRange: range => {
-      ++count;
-      Assert.equal(range.toString(), findText, "Text content should match");
+    listener: {
+      onIteratorRangeFound(range) {
+        ++count;
+        Assert.equal(range.toString(), findText, "Text content should match");
+      }
     },
     word: findText
   });
@@ -55,6 +57,8 @@ add_task(function* test_start() {
   Assert.equal(rangeCount, count, "Amount of ranges yielded should match!");
   Assert.ok(!FinderIterator.running, "Running state should match");
   Assert.equal(FinderIterator._previousRanges.length, rangeCount, "Ranges cache should match");
+
+  FinderIterator.reset();
 });
 
 add_task(function* test_valid_arguments() {
@@ -68,7 +72,7 @@ add_task(function* test_valid_arguments() {
     caseSensitive: false,
     entireWord: false,
     finder: gMockFinder,
-    onRange: range => ++count,
+    listener: { onIteratorRangeFound(range) { ++count; } },
     word: findText
   });
 
@@ -80,14 +84,14 @@ add_task(function* test_valid_arguments() {
   count = 0;
   Assert.throws(() => FinderIterator.start({
     entireWord: false,
-    onRange: range => ++count,
+    listener: { onIteratorRangeFound(range) { ++count; } },
     word: findText
   }), /Missing required option 'caseSensitive'/, "Should throw when missing an argument");
   FinderIterator.reset();
 
   Assert.throws(() => FinderIterator.start({
     caseSensitive: false,
-    onRange: range => ++count,
+    listener: { onIteratorRangeFound(range) { ++count; } },
     word: findText
   }), /Missing required option 'entireWord'/, "Should throw when missing an argument");
   FinderIterator.reset();
@@ -95,7 +99,7 @@ add_task(function* test_valid_arguments() {
   Assert.throws(() => FinderIterator.start({
     caseSensitive: false,
     entireWord: false,
-    onRange: range => ++count,
+    listener: { onIteratorRangeFound(range) { ++count; } },
     word: findText
   }), /Missing required option 'finder'/, "Should throw when missing an argument");
   FinderIterator.reset();
@@ -105,14 +109,14 @@ add_task(function* test_valid_arguments() {
     entireWord: false,
     finder: gMockFinder,
     word: findText
-  }), /Missing valid, required option 'onRange'/, "Should throw when missing an argument");
+  }), /Missing valid, required option 'listener'/, "Should throw when missing an argument");
   FinderIterator.reset();
 
   Assert.throws(() => FinderIterator.start({
     caseSensitive: false,
     entireWord: true,
     finder: gMockFinder,
-    onRange: range => ++count
+    listener: { onIteratorRangeFound(range) { ++count; } },
   }), /Missing required option 'word'/, "Should throw when missing an argument");
   FinderIterator.reset();
 
@@ -129,7 +133,7 @@ add_task(function* test_stop() {
     caseSensitive: false,
     entireWord: false,
     finder: gMockFinder,
-    onRange: range => ++count,
+    listener: { onIteratorRangeFound(range) { ++count; } },
     word: findText
   });
 
@@ -138,6 +142,8 @@ add_task(function* test_stop() {
   yield whenDone;
 
   Assert.equal(count, 100, "Number of ranges should match `kIterationSizeMax`");
+
+  FinderIterator.reset();
 });
 
 add_task(function* test_reset() {
@@ -150,7 +156,7 @@ add_task(function* test_reset() {
     caseSensitive: false,
     entireWord: false,
     finder: gMockFinder,
-    onRange: range => ++count,
+    listener: { onIteratorRangeFound(range) { ++count; } },
     word: findText
   });
 
@@ -181,12 +187,12 @@ add_task(function* test_parallel_starts() {
     caseSensitive: false,
     entireWord: false,
     finder: gMockFinder,
-    onRange: range => ++count,
+    listener: { onIteratorRangeFound(range) { ++count; } },
     word: findText
   });
 
   // Start again after a few milliseconds.
-  yield new Promise(resolve => gMockWindow.setTimeout(resolve, 2));
+  yield new Promise(resolve => gMockWindow.setTimeout(resolve, 20));
   Assert.ok(FinderIterator.running, "We ought to be running here");
 
   let count2 = 0;
@@ -194,7 +200,7 @@ add_task(function* test_parallel_starts() {
     caseSensitive: false,
     entireWord: false,
     finder: gMockFinder,
-    onRange: range => ++count2,
+    listener: { onIteratorRangeFound(range) { ++count2; } },
     word: findText
   });
 
@@ -212,5 +218,5 @@ add_task(function* test_parallel_starts() {
   Assert.greater(count2, FinderIterator.kIterationSizeMax, "At least one range should've been found");
   Assert.less(count2, rangeCount, "Not all ranges should've been found");
 
-  Assert.less(count2, count, "The second start was later, so should have fewer results");
+  Assert.equal(count2, count, "The second start was later, but should have caught up");
 });