There are some "are you sure you want to quit" Firefox extensions that meet your needs. https://addons.mozilla.org/en-US/firefox/addon/disable-ctrl-q-and-cmd-q

There are some "are you sure you want to quit" Firefox extensions that meet your needs. https://addons.mozilla.org/en-US/firefox/addon/disable-ctrl-q-and-cmd-q/ https://addons.mozilla.org/en-US/firefox/addon/disable-ctrl-... Command-delete works as expected for me (in this HN comment box), deleting only the text on the current line before the cursor.