When having tabwin open and hovering with the mouse over the selected item in the list, the selected item (aka tabwin_widget->selected) will not receive focus anymore on the cb_window_button_leave. I fixed the problem by ensuring that if the previously hovered item was also selected regains the GTK_STATE_FLAG_CHECKED.
Created attachment 9384 Ensure the selected window remains selected after hovering
Simon Steinbeiss referenced this bugreport in commit f41e57e1b4086bb1f586c0ee79e3856f092a128b tabwin: Ensure selected windows remain selected https://git.xfce.org/xfce/xfwm4/commit?id=f41e57e1b4086bb1f586c0ee79e3856f092a128b
Simon Steinbeiss referenced this bugreport in commit 0c5c22f0014d246ad97c2864262ed88faecfd976 tabwin: Ensure selected windows remain selected https://git.xfce.org/xfce/xfwm4/commit?id=0c5c22f0014d246ad97c2864262ed88faecfd976