MapSprite.png doesn't save, which causes TileData.png to be lost as well.

Whenever you open the editor, the MapSprite.png file is overwritten with a blank one, and you have to constantly call for the file again. Additionally, if you have a TileData.png made and you're working on it with that map, saving the tiledata deletes the MapSprite again. This makes it practically impossible to work on anything without constantly making copies of your TileData, which gets deleted everytime you re-import your MapSprite.