I just did an upgrade to the latest version. I have a Macbook Pro 13" (from 2011), but I view it on a 23" screen. Typically, when Parallels comes up, I stretch it out to the full width of the screen and get a lot more room. The icons and everything else stay the same size. It all looks fine. After the upgrade, when Parallels comes up it only takes up about 70% of the screen width. But when I stretch our the parallels window, i don't gain any room. instead, all of the icons are stretched wide. when I open word, all of the letters are wide. i tried a bunch of different configuration settings, full screen view, etc. nothing has fixed it. i don't want to have to work in a 70% screen size. thanks!
Reinstall Parallels tools. It sounds like the Windows resolution is not changing to the resolution of the external display. Reinstalling the tools should fix this. Steve