Hey, You will have to use an extension to change the default keyboard shortcuts. https://support.mozilla.org/en-US/questions/1287036 https://addons.mozilla.org/en-US/firefox/addon/shortkeys/

this extension seems to only allow adding new keyboard shortcuts. what if i want to disable a default one. specifically i want to disable Alt+Left from going back and Alt+Right from going forward. is this impossible with the current state of things ?

Implement "about:shortcuts" showing all shortcuts and allowing the editing of shortcuts

If you're running Windows I'd suggest installing AutoHotkey. Then run the program, follow the instructions on how to create a script file, and place the following code in the file:

$!Left::

   ifWinActive, ahk_exe firefox.exe
   {
       return 
   } else {
       Send !Left
       return
   }

$!Right::

   ifWinActive, ahk_exe firefox.exe
   {
       return 
   } else {
       Send !Right
       return
   }

Then save the file, run it, and place it in the Windows Startup folder. Alt+Left and Alt+Right should then be disabled permanently for Firefox.

Hey, Posting some more support links to help you with this issue. Please go through the steps and let me know if the problem was resolved. https://support.mozilla.org/en-US/questions/1241294 https://support.mozilla.org/en-US/questions/987351#answer-537172