Comment 6 for bug 275528

Here's a Temporal workaround if you're using compiz:
Go to Compiz-Config Settings Manager (install it if you don't have it) and in Window Decorations replace 'any' with '!(class=SeamlessRDP)' or if you have other options you can just add '&!(class=SeamlessRDP)' at the end (everything without the quotes). Note that if you grab it by the windows border it may be a little lag before it updates the position of the window, but if you alt+grab it, everything's fine