--- a/im/content/tabbrowser.xml
+++ b/im/content/tabbrowser.xml
@@ -19,17 +19,17 @@
 
   <binding id="tabbrowser">
     <resources>
       <stylesheet src="chrome://instantbird/content/tabbrowser.css"/>
     </resources>
 
     <content>
       <xul:stringbundle anonid="tbstringbundle" src="chrome://instantbird/locale/tabbrowser.properties"/>
-      <xul:tabbox anonid="tabbox" flex="1" eventnode="document" xbl:inherits="handleCtrlPageUpDown"
+      <xul:tabbox anonid="tabbox" flex="1" eventnode="document"
                   onselect="if (event.target.localName != 'tabpanels') return;
                             document.getBindingParent(this).updateCurrentTab();">
         <xul:hbox class="tab-drop-indicator-bar" collapsed="true" chromedir="&locale.dir;"
                   ondragover="document.getBindingParent(this)._onDragOver(event);"
                   ondragleave="document.getBindingParent(this)._onDragLeave(event);"
                   ondrop="document.getBindingParent(this)._onDrop(event);">
           <xul:hbox class="tab-drop-indicator" mousethrough="always"/>
         </xul:hbox>
@@ -1393,18 +1393,17 @@
                   aEvent.preventDefault();
               }
               return;
             }
 #else
           if (('ctrlKey' in aEvent && aEvent.ctrlKey) &&
               !('shiftKey' in aEvent && aEvent.shiftKey) &&
               !('metaKey' in aEvent && aEvent.metaKey)) {
-            if (aEvent.keyCode == KeyEvent.DOM_VK_F4 &&
-                this.tabbrowser.mTabBox.handleCtrlPageUpDown) {
+            if (aEvent.keyCode == KeyEvent.DOM_VK_F4) {
               this.tabbrowser.removeCurrentTab();
 
               aEvent.stopPropagation();
               aEvent.preventDefault();
               return;
             }
 #endif
             if (aEvent.originalTarget.localName == "tab") {

--- a/mail/base/content/tabmail.xml
+++ b/mail/base/content/tabmail.xml
@@ -263,17 +263,17 @@
     -  otherwise.
     -->
   <binding id="tabmail">
     <resources>
       <stylesheet src="chrome://messenger/content/tabmail.css"/>
       <stylesheet src="chrome://messenger/skin/tabmail.css"/>
     </resources>
     <content>
-      <xul:tabbox anonid="tabbox" class="tabmail-tabbox" flex="1" eventnode="document" xbl:inherits="handleCtrlPageUpDown">
+      <xul:tabbox anonid="tabbox" class="tabmail-tabbox" flex="1" eventnode="document">
         <!-- Remember, user of this binding, you need to provide tabpanels!  -->
         <children includes="tabpanels"/>
       </xul:tabbox>
     </content>
 
     <implementation implements="nsIController">
       <constructor>
         window.controllers.insertControllerAt(0, this);

--- a/suite/browser/tabbrowser.xml
+++ b/suite/browser/tabbrowser.xml
@@ -17,17 +17,17 @@
 
   <binding id="tabbrowser">
     <resources>
       <stylesheet src="chrome://navigator/skin/tabbrowser.css"/>
     </resources>
 
     <content>
       <xul:stringbundle anonid="tbstringbundle" src="chrome://navigator/locale/tabbrowser.properties"/>
-      <xul:tabbox anonid="tabbox" flex="1" eventnode="document" xbl:inherits="handleCtrlPageUpDown">
+      <xul:tabbox anonid="tabbox" flex="1" eventnode="document">
         <xul:hbox class="tab-drop-indicator-bar" collapsed="true">
           <xul:image class="tab-drop-indicator" mousethrough="always"/>
         </xul:hbox>
         <xul:hbox class="tabbrowser-strip" collapsed="true" tooltip="_child" context="_child"
                   anonid="strip"
                   ondragstart="this.parentNode.parentNode._onDragStart(event);"
                   ondragover="this.parentNode.parentNode._onDragOver(event);"
                   ondrop="this.parentNode.parentNode._onDrop(event);"
@@ -1664,17 +1664,17 @@
               try {
                 b.loadURIWithFlags(aURI, {
                   flags,
                   triggeringPrincipal : aTriggeringPrincipal,
                   referrerURI: aReferrerURI,
                   charset: aCharset,
                   referrerPolicy: aReferrerPolicy,
                   postData: aPostData,
-                });                
+                });
               }
               catch (ex) { }
             }
 
             t.dispatchEvent(new Event("TabOpen",
               { bubbles: true, cancelable: false }));
 
             // Check if we're opening a tab related to the current tab and

--- a/suite/mailnews/tabmail.xml
+++ b/suite/mailnews/tabmail.xml
@@ -158,17 +158,16 @@
            extends="chrome://navigator/content/tabbrowser.xml#tabbrowser">
     <resources>
       <stylesheet src="chrome://navigator/skin/tabbrowser.css"/>
     </resources>
     <content>
       <xul:tabbox anonid="tabbox"
                   flex="1"
                   eventnode="document"
-                  xbl:inherits="handleCtrlPageUpDown"
                   onselect="if (event.target.localName == 'tabs' &amp;&amp;
                                 'updateCurrentTab' in this.parentNode)
                               this.parentNode.updateCurrentTab();">
         <xul:hbox class="tab-drop-indicator-bar" collapsed="true">
           <xul:hbox class="tab-drop-indicator" mousethrough="always"/>
         </xul:hbox>
         <xul:hbox class="tabbrowser-strip tabmail-strip"
                   tooltip="_child"