http://bugs.winehq.org/show_bug.cgi?id=19889
--- Comment #9 from diafero@arcor.de 2010-06-17 05:37:15 --- (In reply to comment #8)
After opening some of the dialog windows (most notable the "Preferences") there might be big problems trying to close them. When you click on the "x" (cross) at the top of the dialog window it (the dialog window) becomes "milk-gray colored" for about a second and then reappears back. It takes numerous times clicking on "x" to get the dialog window finally close.
Yes, I do have that, too (and sometimes even for drop-down menus). It seems to me that taking away and giving focus again using the task-bar helps to make the window actually close. It's not just the preferences window, though, I had it at least once with almost every sub-window steam opens.