Double-clicking on the title bar crashes the browser. The crash recovery
dialog box comes up. Clicking on restart does not start it back up.

**
Gdk:ERROR:../../../../../gdk/x11/gdkwindow-x11.c:5165:create_moveresize_window: assertion failed: (mv_resize->moveresize_emulation_window == NULL)
Redirecting call to abort() to mozalloc_abort

ExceptionHandler::GenerateDump cloned child ExceptionHandler::WaitForContinueSignal waiting for continue signal...
14300
ExceptionHandler::SendContinueSignalToChild sent continue signal to child

This seems easily reproducible, just create a test user, log in with xmonad,
alt-shift-return to open terminal, run firefox. May also affect other tiling WMs
that don't support moving windows.

firefox-esr also has the problem.