Take in mind that upgrading the shell you're also using libmutter-10 instead of libmutter-9, so the problem may be anywhere in both (more likely in mutter).
So the only way to find out what may have changed this is using git bisect over the various mutter versions (might be annoying, because you need to keep shell in sync with that). If the unconfined snap isn't affected, could be that mutter is now using something that is blocked by the confinement? -- 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