diff --git a/browser/base/content/urlbarBindings.xml b/browser/base/content/urlbarBindings.xml
index cee8fc9bcde3..7f040bf8c5a8 100644
--- a/browser/base/content/urlbarBindings.xml
+++ b/browser/base/content/urlbarBindings.xml
@@ -255,6 +255,7 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
       <method name="onKeyPress">
         <parameter name="aEvent"/>
+        <parameter name="aNoDefer"/>
         <body><![CDATA[
           switch (aEvent.keyCode) {
             case KeyEvent.DOM_VK_LEFT:
@@ -276,7 +277,7 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
               break;
           }
           if (!this.popup.disableKeyNavigation) {
-            if (this._shouldDeferKeyEvent(aEvent)) {
+            if (!aNoDefer && this._shouldDeferKeyEvent(aEvent)) {
               this._deferKeyEvent(aEvent, "onKeyPress");
               return false;
             }
@@ -309,9 +310,9 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
         <body><![CDATA[
           // If any event has been deferred for this search, then defer all
           // subsequent events so that the user does not experience any
-          // keypresses out of order.  All events will be replayed when this
-          // timeout fires.
-          if (this._deferredKeyEventTimeout) {
+          // keypresses out of order.  All events will be replayed when
+          // _deferredKeyEventTimeout fires.
+          if (this._deferredKeyEventQueue.length) {
             return true;
           }
 
@@ -356,6 +357,11 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
       <method name="_safeToPlayDeferredKeyEvent">
         <parameter name="event"/>
         <body><![CDATA[
+          if (event.keyCode == KeyEvent.DOM_VK_RETURN) {
+            return this.popup.selectedIndex != 0 ||
+                   this.gotResultForCurrentQuery;
+          }
+
           if (!this.gotResultForCurrentQuery || !this.popupOpen) {
             // We're still waiting on the first result, or the popup hasn't
             // opened yet, so not safe.
@@ -390,7 +396,9 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
                The key event to defer.
         @param methodName
                The name of the method on `this` to call.  It's expected to take
-               a single argument, the event.
+               two arguments: the event, and a noDefer bool.  If the bool is
+               true, then the event is being replayed and it should not be
+               deferred.
       -->
       <method name="_deferKeyEvent">
         <parameter name="event"/>
@@ -402,6 +410,9 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
           // defaultPrevented.  That's the purpose of this expando.  If we could
           // figure out what's setting defaultPrevented and prevent it, then we
           // could get rid of this.
+          if (event.urlbarDeferred) {
+            throw new Error("Key event already deferred!");
+          }
           event.urlbarDeferred = true;
 
           this._deferredKeyEventQueue.push({
@@ -419,20 +430,17 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
             // the user's input.
             let elapsed = Cu.now() - this._searchStartDate;
             let remaining = this._deferredKeyEventTimeoutMs - elapsed;
-            if (remaining <= 0) {
+            this._deferredKeyEventTimeout = setTimeout(() => {
               this.replayAllDeferredKeyEvents();
-            } else {
-              this._deferredKeyEventTimeout = setTimeout(() => {
-                this.replayAllDeferredKeyEvents();
-                this._deferredKeyEventTimeout = null;
-              }, remaining);
-            }
+              this._deferredKeyEventTimeout = null;
+            }, Math.max(0, remaining));
           }
         ]]></body>
       </method>
 
       <!-- The enter key is always deferred, so it's not included here. -->
       <field name="_keyCodesToDefer">new Set([
+        KeyboardEvent.DOM_VK_RETURN,
         KeyboardEvent.DOM_VK_DOWN,
         KeyboardEvent.DOM_VK_TAB,
       ])</field>
@@ -482,7 +490,7 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
         <body><![CDATA[
           // Safety check: handle only if the search string didn't change.
           if (this.mController.searchString == instance.searchString) {
-            this[instance.methodName](instance.event);
+            this[instance.methodName](instance.event, true);
           }
         ]]></body>
       </method>
@@ -1481,6 +1489,7 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
       <method name="handleEnter">
         <parameter name="event"/>
+        <parameter name="noDefer"/>
         <body><![CDATA[
           // We need to ensure we're using a selected autocomplete result.
           // A result should automatically be selected by default,
@@ -1500,30 +1509,29 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
           // which will be called as a result of mController.handleEnter().
           this.handleEnterSearchString = this.mController.searchString;
 
-          if (!this._deferredKeyEventQueue.length &&
-              (this.popup.selectedIndex != 0 || this.gotResultForCurrentQuery)) {
-            let canonizeValue = this.value;
-            if (event.shiftKey || (AppConstants.platform === "macosx" ?
-                                   event.metaKey :
-                                   event.ctrlKey)) {
-              let action = this._parseActionUrl(canonizeValue);
-              if (action && "searchSuggestion" in action.params) {
-                canonizeValue = action.params.searchSuggestion;
-              } else if (this.popup.selectedIndex === 0 &&
-                         this.mController.getStyleAt(0).includes("autofill")) {
-                canonizeValue = this.handleEnterSearchString;
-              }
-            }
-            this.maybeCanonizeURL(event, canonizeValue);
-            let handled = this.mController.handleEnter(false, event);
-            this.handleEnterSearchString = null;
-            this.popup.overrideValue = null;
-            return handled;
+          if (!noDefer && this._shouldDeferKeyEvent(event)) {
+            // Defer the event until the first non-heuristic result comes in.
+            this._deferKeyEvent(event, "handleEnter");
+            return false;
           }
 
-          // Defer the event until the first non-heuristic result comes in.
-          this._deferKeyEvent(event, "handleEnter");
-          return false;
+          let canonizeValue = this.value;
+          if (event.shiftKey || (AppConstants.platform === "macosx" ?
+                                 event.metaKey :
+                                 event.ctrlKey)) {
+            let action = this._parseActionUrl(canonizeValue);
+            if (action && "searchSuggestion" in action.params) {
+              canonizeValue = action.params.searchSuggestion;
+            } else if (this.popup.selectedIndex === 0 &&
+                       this.mController.getStyleAt(0).includes("autofill")) {
+              canonizeValue = this.handleEnterSearchString;
+            }
+          }
+          this.maybeCanonizeURL(event, canonizeValue);
+          let handled = this.mController.handleEnter(false, event);
+          this.handleEnterSearchString = null;
+          this.popup.overrideValue = null;
+          return handled;
         ]]></body>
       </method>
 
