When authoring my own DVDs, DVDAuthorGUI is working better than any other tool I’ve tried, apart from this one problem: the preview portion of the Menu Editor window is always black. It reacts to left mouse button clicks by flashing the actual background, which has thus far made it just barely usable.
Installing DScaler didn’t help, neither did wiggling the different decoders’ priorities using DSFMgr (both linked to from DVDAuthorGUI’s download page).
I just discovered that by changing the number of frames from 1 to 100 when creating the m2v still, it actually stays visible (when clicked) long enough to be able to place the buttons. But it’s still pretty damn difficult and most likely not how it’s intented to behave. I think I’m going to try to work around this by making the m2v still long enough to be useful, and replacing it with a single-frame still after having positioned the buttons.