I love this program, but it took me way too many confusing clicks to realize that 'add normal' and 'delete normal' are reversed in the context menu; that is, 'delete normal' opens the window to add a normal map, while 'add normal' simply deletes the attached normal map, or the sprite itself if there's no normal attached. The only reason I discovered exactly what was happening, was that I spent all last night learning how to generate and edit normal maps.
Please make sure that when you correct this you add it prominently in patch notes or I, personally, might make some very frustrating errors lol.