Firefox "Close all tabs" dialog hangs WM.

[Rabbit-i286]

As you probably know, when gracefully attempting to close any multi-tab Firefox window using either an EWMH WM's internal protocol (bound by default to Super + shift + c, as you know), or xdotool's windowquit function, Firefox 93.0 dims its interface and displays a dialog box (not a true child window, I think) asking if the user really wishes to close all tabs.

The issue is that when running Frankenwm (-v does not show a numerical version but it appears to be the most recent commit, as I installed it in the last month, and frankenwm.c has not been modified for four) on the Xorg 1.20.13 X11 server on Arch Linux 5.14.12-arch1-1, configured with no integrated bar and no scratchpad, the WM appears to hang to a greater or lesser extent whenever Firefox displays this dialog, especially if the user clicks "cancel" on the dialog. On occasion and only when invoked with super-shift-c, confirming the action in the dialog box will allow the window to be sucessfully unmapped with no ill effects.

Otherwise, the firefox window remains mapped, frozen and displaying as if focused, while the program apparently exits successfully, according to ps -e from another TTY. After this the WM does not respond to most or all internal keybindings. In some cases xbindkeys can still start a terminal and the window will sometimes display correctly. At no time can the user change desktops.

I usually have aur/compton-old-git, xmobar and xbindkeys running when this happens, but I have reproduced it with none of these running.

Thanks!