If you connect rdesktop to XRDP 0.6.0 server in a full screen mode and then switch to window mode by pressing Ctrl + Alt + Enter rdesktop will display initially a black screen. When you start draggin something over rdesktop screen - parts of the screen are refreshed (working more like a brush clearing the background). A full screen refresh clears the black veil. Each time I switch from full to window or vice versa I mimimize the screen at the remote to fix black veil problem. I'm not sure if it's rdesktop or xrdp bug so I'm filing it to both parties.