Unfortunately, there is no built-in way to disable the shortcut. Websites ''can'' intercept Ctrl+B/Command+B and prevent Firefox from receiving it, but they do need to use modern code. Older code no longer works as of a few years ago. If you think the site might have legacy code, you can make some exceptions for the site. You didn't mention the address, but let's take www.example''.''com as an example. Here's how you would make the exceptions: (1) In a new tab, type or paste '''about:config''' in the address bar and press Enter/Return. Click the button accepting the risk. ''More info on about:config:'' [[Configuration Editor for Firefox]]. ''The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.'' (2) In the search box in the page, type or paste '''keypress.hack''' and pause while the list is filtered ''Firefox should display four preferences containing this text. The two you can edit have "addl" at the end of their names.'' (3) Double-click the '''dom.keyboardevent.keypress.hack.dispatch_non_printable_keys.addl''' preference to display an editing field, and enter '''www.example''.''com''' then press Enter or click the blue check mark button to save the change. Note: to list multiple host names, separate them with commas. (4) Double-click the '''dom.keyboardevent.keypress.hack.use_legacy_keycode_and_charcode.addl''' preference to display an editing field, and enter '''www.example''.''com''' then press Enter or click the blue check mark button to save the change. Note: to list multiple host names, separate them with commas. Hopefully one of those will help.