I bisected mutter and gnome-shell until I identified the revision in mutter that caused the regression: https://gitlab.gnome.org/GNOME/mutter/-/commit/26676a829e74859488154cd8c45de1d0b629f3ca.
More specifically, the changes to src/core/events.c. Indeed I rebuilt mutter in jammy with the following patch, and the issue with the firefox snap was gone: --- a/src/core/events.c +++ b/src/core/events.c @@ -523,10 +523,6 @@ meta_display_handle_event (MetaDisplay #ifdef HAVE_WAYLAND if (wayland_compositor && !bypass_wayland) { - if (window && event->type == CLUTTER_MOTION && - event->any.time != CLUTTER_CURRENT_TIME) - meta_window_check_alive_on_event (window, event->any.time); - if (meta_wayland_compositor_handle_event (wayland_compositor, event)) bypass_clutter = TRUE; } -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to firefox in Ubuntu. https://bugs.launchpad.net/bugs/1964541 Title: Cannot rearrange Firefox (snap) browser tabs/bookmarks in gnome-shell 42 (Wayland session) Status in Mozilla Firefox: New Status in firefox package in Ubuntu: Confirmed Bug description: Since 42~beta-1ubuntu1, and still present in 42~beta-1ubuntu2, attempting to re-arrange tabs in Firefox fails. Click and drag the tab and release, nothing changes. The next click to the tab is ignored. syslog has the following: Mar 11 13:06:47 desktop firefox[2192]: Attempting to add a widget with type GtkWindow to a container of type GtkWindow, but the widget is already inside a container of type GtkWindow, please remove the widget from its existing container first. Mar 11 13:06:48 desktop firefox[2192]: Attempting to add a widget with type GtkWindow to a container of type GtkWindow, but the widget is already inside a container of type GtkWindow, please remove the widget from its existing container first. Mar 11 13:06:50 desktop firefox[2192]: Attempting to add a widget with type GtkWindow to a container of type GtkWindow, but the widget is already inside a container of type GtkWindow, please remove the widget from its existing container first. Mar 11 13:06:51 desktop firefox[2192]: Attempting to add a widget with type GtkWindow to a container of type GtkWindow, but the widget is already inside a container of type GtkWindow, please remove the widget from its existing container first. gnome-shell 42~beta-1ubuntu2 Firefox Snap 98.0-3 (1073) To manage notifications about this bug go to: https://bugs.launchpad.net/firefox/+bug/1964541/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp