So, in fact this bug has been fixed by the fix for https://bugzilla.mozilla.org/show_bug.cgi?id=1192655 -- pressing Alt plus a letter when in fullscreen mode no longer opens hidden menus, and thus pressing F11 to get out of fullscreen mode will always work.
The desire of the other bug report (https://bugzilla.mozilla.org/show_bug.cgi?id=648504) is that Alt+letter should open the requested menu *visibly*, so that the menus can be used even when the menu bar itself is hidden.
So, in fact this bug has been fixed by the fix for https:/ /bugzilla. mozilla. org/show_ bug.cgi? id=1192655 -- pressing Alt plus a letter when in fullscreen mode no longer opens hidden menus, and thus pressing F11 to get out of fullscreen mode will always work.
The desire of the other bug report (https:/ /bugzilla. mozilla. org/show_ bug.cgi? id=648504) is that Alt+letter should open the requested menu *visibly*, so that the menus can be used even when the menu bar itself is hidden.