Windows 10 64 bit. I've reproduced the problem with a clean config by opening a bunch of floating tool-windows - see screenshot or open the attached config zip. The toolwindow that gets the focus is search results - but in my normal slick 25.0.2 config it is preview/ references/ backup history - whichever one of this group was last in front when I closed slick - so it's probably not the focused tool-window that causes it. It's fairly minor, I've put up with it for a while.