Thanks again for the comments! I've pushed out an update with the following changes:
- The cursor now shows the current hex you are painting with.
- There is one level of Undo, it undoes the most recent paint operation.
- As suggested, I've added the remaining hex rotations and replaced the crowded buttons with a single button for each type. There are new buttons for Rotate Right, Rotate Left, and Flip, which allow you to rotate any of the basic shapes instead.
- I rearranged the buttons slightly, moving Clear Map back up with the basic paint options.
More changes ahead, including symbology hexes for Dungeon and Terrain maps.