Vinagre - remote desktop viewer, control
configuration
There doesn't seem to be any.
help
stuck in full screen
position the mouse cursor in the top center of the screen. Now the "local" mouse cursor should become visible. Once visible, you have keyboard shortcut control of the local desktop not the remote desktop. Now you can alt-tab. If the cursor is not visible in the top center of the screen all control reverts back to the remote desktop.