diff --git a/toolkit/content/widgets/browser.xml b/toolkit/content/widgets/browser.xml
index 3d05da187c26..1311ea986cd0 100644
--- a/toolkit/content/widgets/browser.xml
+++ b/toolkit/content/widgets/browser.xml
@@ -813,9 +813,9 @@
     </implementation>
 
     <handlers>
-      <handler event="keypress" keycode="VK_F7">
+      <handler event="keypress" keycode="VK_F7" group="system">
         <![CDATA[
-          if (!event.isTrusted)
+          if (event.getPreventDefault() || !event.isTrusted)
             return;
 
           // Toggle browse with caret mode
diff --git a/xpfe/global/resources/content/bindings/browser.xml b/xpfe/global/resources/content/bindings/browser.xml
index a8db6e2d49aa..ca6f1403edfa 100644
--- a/xpfe/global/resources/content/bindings/browser.xml
+++ b/xpfe/global/resources/content/bindings/browser.xml
@@ -395,9 +395,9 @@
     </implementation>
 
     <handlers>
-      <handler event="keypress" keycode="VK_F7">
+      <handler event="keypress" keycode="VK_F7" group="system">
         <![CDATA[
-          if (!event.isTrusted)
+          if (event.getPreventDefault() || !event.isTrusted)
             return;
 
           // Toggle browse with caret mode