Add the keys used by the back/forward menu items to the accelerator map so th...

app/resources/app_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <!-- This file contains definitions of resources that will be translated for
 each locale. Specifically, these are UI strings that are used by app/ that
 need to be translated for each locale.-->
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       source_lang_id="en" enc_check="möl">
   <outputs>
     <!-- TODO add each of your output files.  Modify the three below, and add
@@ skipping 286 matching lines @@
       </message>
       <message name="IDS_APP_ENTER_KEY" desc="Enter key">
         Enter
       </message>
       <message name="IDS_APP_F1_KEY" desc="F1 key">
         F1
       </message>
       <message name="IDS_APP_F11_KEY" desc="F11 key">
         F11
       </message>
+      <message name="IDS_APP_BACKSPACE_KEY" desc="Backspace key">
+        Backspace
+      </message>
 
       <!-- Shortcut Modifiers -->
       <message name="IDS_APP_CONTROL_MODIFIER" desc="Control key shortcut modifier">
         Ctrl+<ph name="KEY_COMBO_NAME">$1<ex>C</ex></ph>
       </message>
       <message name="IDS_APP_ALT_MODIFIER" desc="Alt key shortcut modifier">
         Alt+<ph name="KEY_COMBO_NAME">$1<ex>C</ex></ph>
       </message>
       <message name="IDS_APP_SHIFT_MODIFIER" desc="Shift key shortcut modifier">
         Shift+<ph name="KEY_COMBO_NAME">$1<ex>C</ex></ph>
       </message>
       
     </messages>
   </release>
 </grit>