This isn't so much a bug as a self-contradiction. When you save a quest (in the editor), and don't make any changes, you can't select file->save again until another change is made. However, you can still press F2 to save.
F2 save w/ no change
Quite true, but, should there be a feature that doesn't count as a change in ZQuest's proverbial eyes, then if you make that change and try to save, you can't.
I suppose this should only be considered after a bug-free release for that reason. :shrug:
I just think it should be consistent either way, that's all. Maybe it wasn't worth mentioning.
Quite the minor bug, but fixed in the next build.
If you need to save and ZQuest won't let you, you can always Save As and overwrite the current quest file anyway.