I am running Parallels 12.2.1 on an iMac and on a MacBook Pro. Until recently, both worked fine. Now, however, I cannot fully resize the window on the MacBook. I can stretch it proportionally by pulling down diagonally on a corner. However, the main Windows program that I use most often needs more lateral space. On the iMac, I can stretch the window to make it wider by pulling on the sides. On the MacBook, although the double-headed arrows show up when I hover on a side line, the window will not stretch. I have compared and the Parallels configurations for both machines are identical. This change is fairly recent in that I previously had no problem stretching the MacBook window laterally just as I do on the iMac. Any ideas?