Since I upgraded to 4.8, my window buttons have been behaving strangely. After working for a bit through the day, my windows buttons start to multiply, attaching themselves to the wrong windows and then soon go out of control. I have to restart the panel to get things back to normal. It usually seems to happen when I open Sylpheed, as everything suddenly becomes 10s to 100s of Sylpheed windows, but I've had it tell me that Firefox was one of 20 terminal windows too. It seems fairly random what the buttons believe they belong to (according to the frame that appears on hover), but most don't do anything.
I noticed that I can make this happen with Sylpheed by minimizing the window and maximizing it again. Every time I maximize it again, a new window button appears. If I do it enough times, it will start replacing existing buttons. Sometimes I can fix it by switching to a new virtual workspace and back after killing Sylpheed. So far, it only appears to happen with Sylpheed, so I'm not sure whether the buttons were broken and masking a problem with Sylpheed before, or they were correct before and are now broken.
Tried this multiple times, but it seems to work fine here. Do you still have this problem with panel 4.8.5?
Nope. Looks like the problem doesn't exist anymore in 4.8.5. Thanks!