diff --git a/accessible/tests/mochitest/relations/test_tabbrowser.xul b/accessible/tests/mochitest/relations/test_tabbrowser.xul
index 0a9cdd88392c..42e59f00f6ee 100644
--- a/accessible/tests/mochitest/relations/test_tabbrowser.xul
+++ b/accessible/tests/mochitest/relations/test_tabbrowser.xul
@@ -49,7 +49,7 @@
         // 'labelled by'/'label for' relations for xul:tab and xul:tabpanel
 
         var tabs = tabBrowser().tabContainer.childNodes;
-        var panels = tabBrowser().mTabBox.tabpanels.childNodes;
+        var panels = tabBrowser().tabbox.tabpanels.childNodes;
 
         testRelation(panels[0], RELATION_LABELLED_BY, tabs[0]);
         testRelation(tabs[0], RELATION_LABEL_FOR, panels[0]);
diff --git a/accessible/tests/mochitest/tree/test_tabbrowser.xul b/accessible/tests/mochitest/tree/test_tabbrowser.xul
index 4f3f05a66aff..b17d0012b84b 100644
--- a/accessible/tests/mochitest/tree/test_tabbrowser.xul
+++ b/accessible/tests/mochitest/tree/test_tabbrowser.xul
@@ -213,7 +213,7 @@
           ]
         };
 
-        testAccessibleTree(tabBrowser().mTabBox.tabpanels, tabboxAccTree);
+        testAccessibleTree(tabBrowser().tabbox.tabpanels, tabboxAccTree);
       }
 
       this.getID = function testTabHierarchy_getID()
diff --git a/browser/base/content/browser-ctrlTab.js b/browser/base/content/browser-ctrlTab.js
index 19b54cfa76da..3b0d4e80115e 100644
--- a/browser/base/content/browser-ctrlTab.js
+++ b/browser/base/content/browser-ctrlTab.js
@@ -547,7 +547,7 @@ var ctrlTab = {
     tabContainer[toggleEventListener]("TabClose", this);
 
     document[toggleEventListener]("keypress", this);
-    gBrowser.mTabBox.handleCtrlTab = !enable;
+    gBrowser.tabbox.handleCtrlTab = !enable;
 
     if (enable)
       PageThumbs.addExpirationFilter(this);
diff --git a/browser/base/content/tabbrowser.xml b/browser/base/content/tabbrowser.xml
index c9b2da1081f7..ed7590ce204e 100644
--- a/browser/base/content/tabbrowser.xml
+++ b/browser/base/content/tabbrowser.xml
@@ -69,7 +69,7 @@
          Components.classes["@mozilla.org/autocomplete/search;1?name=unifiedcomplete"]
                    .getService(Components.interfaces.mozIPlacesAutoComplete);
       </field>
-      <field name="mTabBox" readonly="true">
+      <field name="tabbox" readonly="true">
         document.getAnonymousElementByAttribute(this, "anonid", "tabbox");
       </field>
       <field name="mPanelContainer" readonly="true">
@@ -3935,10 +3935,10 @@
         <setter>
           <![CDATA[
           if (gNavToolbox.collapsed && !this._allowTabChange) {
-            return this.mTabBox.selectedTab;
+            return this.tabbox.selectedTab;
           }
           // Update the tab
-          this.mTabBox.selectedTab = val;
+          this.tabbox.selectedTab = val;
           return val;
           ]]>
         </setter>
@@ -4625,7 +4625,7 @@
 
                 this.maybeVisibleTabs.add(showTab);
 
-                let tabs = this.tabbrowser.mTabBox.tabs;
+                let tabs = this.tabbrowser.tabbox.tabs;
                 let tabPanel = this.tabbrowser.mPanelContainer;
                 let showPanel = tabs.getRelatedElement(showTab);
                 let index = Array.indexOf(tabPanel.childNodes, showPanel);
@@ -6429,7 +6429,7 @@
       </field>
 
       <field name="tabbox" readonly="true">
-        this.tabbrowser.mTabBox;
+        this.tabbrowser.tabbox;
       </field>
 
       <field name="contextMenu" readonly="true">
diff --git a/browser/base/content/test/general/browser_bug462673.js b/browser/base/content/test/general/browser_bug462673.js
index 96f44a2ca441..ba7af37f0200 100644
--- a/browser/base/content/test/general/browser_bug462673.js
+++ b/browser/base/content/test/general/browser_bug462673.js
@@ -29,7 +29,7 @@ add_task(async function() {
     is(win.gBrowser.browsers.length, 1, "Window has one browser");
     is(win.gBrowser.selectedTab, newTab, "Remaining tab is selected");
     is(win.gBrowser.selectedBrowser, newBrowser, "Browser for remaining tab is selected");
-    is(win.gBrowser.mTabBox.selectedPanel, newBrowser.parentNode.parentNode.parentNode.parentNode, "Panel for remaining tab is selected");
+    is(win.gBrowser.tabbox.selectedPanel, newBrowser.parentNode.parentNode.parentNode.parentNode, "Panel for remaining tab is selected");
   }
 
   await promiseWindowClosed(win);
diff --git a/browser/base/content/test/general/browser_tabkeynavigation.js b/browser/base/content/test/general/browser_tabkeynavigation.js
index 837ac587e509..fef3df18c20d 100644
--- a/browser/base/content/test/general/browser_tabkeynavigation.js
+++ b/browser/base/content/test/general/browser_tabkeynavigation.js
@@ -57,11 +57,11 @@ add_task(async function test() {
   is(gBrowser.selectedTab, tab1,
      "Tab1 should be activated by pressing Ctrl+PageUp on Tab2");
 
-  if (gBrowser.mTabBox._handleMetaAltArrows) {
+  if (gBrowser.tabbox._handleMetaAltArrows) {
     gBrowser.selectedTab = tab1;
     browser1.focus();
 
-    let ltr = window.getComputedStyle(gBrowser.mTabBox).direction == "ltr";
+    let ltr = window.getComputedStyle(gBrowser.tabbox).direction == "ltr";
     let advanceKey = ltr ? "VK_RIGHT" : "VK_LEFT";
     let reverseKey = ltr ? "VK_LEFT" : "VK_RIGHT";
 
@@ -109,7 +109,7 @@ add_task(async function test() {
     // XXX Currently, Command + "{" and "}" don't work if keydown event is
     //     consumed because following keypress event isn't fired.
 
-    let ltr = window.getComputedStyle(gBrowser.mTabBox).direction == "ltr";
+    let ltr = window.getComputedStyle(gBrowser.tabbox).direction == "ltr";
     let advanceKey = ltr ? "}" : "{";
     let reverseKey = ltr ? "{" : "}";
 
diff --git a/browser/components/sessionstore/SessionStore.jsm b/browser/components/sessionstore/SessionStore.jsm
index 0e9634370468..0e79b40e6212 100644
--- a/browser/components/sessionstore/SessionStore.jsm
+++ b/browser/components/sessionstore/SessionStore.jsm
@@ -3279,7 +3279,7 @@ var SessionStoreInternal = {
       tabMap.set(tab, tabData);
       tabsData.push(tabData);
     }
-    winData.selected = tabbrowser.mTabBox.selectedIndex + 1;
+    winData.selected = tabbrowser.tabbox.selectedIndex + 1;
 
     this._updateWindowFeatures(aWindow);