Maybe bug 78414?
Another way to resolve it would be to have a setting that allows a user to request that Firefox does not allow applications to override certain keystrokes (Control-L, Control-O, Control-R, Control-T, etc.). As an end-user, I don't really care what the *website* wants to do with Control-L. I want to change the website address from the keyboard. Perhaps having a pop-up to allow the web-page control over the keyboard shortcuts is a bit much. I see nothing wrong with having a setting that allows you to block applications from overriding Firefox's own shortcuts.
You need to log in before you can comment on or make changes to this bug.