Every once in awhile the yellow button on several of my windows will gray out. It doesnt seem to be app specific, although I notice it the most in safari. But it does happen in the finder as well. I thought it was a problem with the OS on my old G5, but I just got a new iMac today. I havent done a system migration or anything like that, the only thing I moved from my old system to the new was my safari bookmarks folder. What is this problem, and what causes it? I just checked all my open apps, the minimize button doesnt work in anything, even if the yellow button isnt grayed out. Apple-M doesnt work either. If I quit and reopen the app, it will work. In the past, a restart of the computer has also fixed this.. but it shouldnt be happening on a brand new iMac!