i am using a new iMac and have had the Mac App Store go to full screen but will not return to normal size no matter what steps I take. I switched to a different user in same iMac and the App Store did not go to full screen. (I didn't use it for long nor did I try to go to full screen and return). I can use the App Store, so it is more an annoyance than a concern. Any suggestions if there is a setting I can make to get it to return to normal? I have restarted the iMac, no change.