Disappearing Gui.

[Edi]

If it's the problem with the list of orders menu not appearing when you hit space with commanders selected (or just click on them to give orders), then that happens with resolutions larger than 1024x768 (or was it larger than 1280x1024 ?). Solution is to hit Esc, move mouse leftward (as usually the menu appears to the right of visible screen space) and try again.

If it's something else, we need more specifics: What part of the GUI, under what conditions and so forth.