Tabs spilling into other window when Tab Group window is closed

[AgentX2006]

Describe the bug When closing a Tab Group window the tabs spillover into the browser window behind it before closing.

To Reproduce Steps to reproduce the behavior:

1. Open Firefox.
2. Open any Tab Group in a new window.
3. Close the new Tab Group window.
4. Watch all the tabs from the closed window spill into

Expected behavior The window and all tabs within it should just close without any spillover.

Screenshots Video of the issue. https://youtu.be/ki3mEPBxnZU

Desktop (please complete the following information):

• Windows 10 Home
• Firefox version: 137.0.1
• Simple Tab Groups version: 5.3.2

Additional context This spillover can lead to the user doing things they didn't intend to do. For example you can click a tab that has spilled over and it is prevented from closing. This interaction is in the linked video. However if you close this tab it is removed from the tab group just as if you had closed the tab from its original Tab Group window. To prevent this you have to once again open the tab group in a new window. This will cause the tab in question to be moved back to the Tab Group window when it opens and will also be the active tab instead of the normal behavior which is the right most tab being the active one when opening a Tab group in a new window. You can then close the Tab Group window again to preserve the Tab Group.

[philg-dev]

I've noticed this kind of bug as well in the past. In my case I think it happened to 100+ tabs at once, so it even made Firefox hang for a few seconds.

I've noticed from your video, that the window with yahoo open is a window that is not assigned to any tab group. I think that's also the only case when this happens. I've only witnessed the issue a few times in the past like 6 months or so and I couldn't figure out at the time what the cause was. It was always pretty scary though, since I've got about 800~1000+ tabs open across all my groups... That's also why I wasn't super keen on experimenting with it.

[AgentX2006]

It happens even between 2 Tab Group windows. It's just harder to notice since a second Tab Group window likely has tabs displayed along the entire length of the window so you don't see them go racing across.

[philg-dev]

Interesting... Maybe in the cases that I've noticed the issue, I closed a window with a very large group then...

In my workflow I rarely close windows individually... I almost always have 2 windows open (one per screen) and when I quit Firefox, I use CTRL + Q to close everything at once. That doesn't cause any issues.

Anyway... hopefully we'll hear back from the Owner about this issue, when they have time to spare...