Comment 17 for bug 176611

The way I got around the problem is by creating a shortcut to rdesktop (as an app, not a console app) and then putting in my arguments thus:

rdesktop -u myusername -g 1275x945 -a 15 -z myhost

By specifying the exact dimensions of the window I can happily have it fill up one of my desktops, not move thanks to snapping edges and be able to easily ctrl+alt+arrow out to another desktop.