IIRC there was a bug in xrdp+unity3d that causes this. I believe using a different window manager will solve the issue.
but question your self: why even use xrdp when you can just use ssh :| Your not in windows anymore, everything in your system is configured in plain text files.
Good question skittle. In my case I need to access my Ubuntu 'desktop' which is talking to the world outside the router. Then rdc to my Windows 7 box to figure out why it's NOT talking to the rest of the world. It's a frigging shame huh?