- Update tile count in title bar after loading tiles
- Support for Sonic 3 & Knuckles' unique DPLC format (used by non-player objects).
- Sprite spacing (figure out what algorithm SonMapEd uses).
- Add scrollbar to tile viewer.
- Don't bother drawing sprites that are off-screen.
- 'Select unmapped tiles' shows that auto-scrolling is still screwy (Sonic 2 Sonic sprites).
- Tall sprites make the sprite viewer taller.
- Extra controls: https://forums.sonicretro.org/index.php?threads/sonmaped-sprite-mappings-editor.8736/
- Save states.
- Remember current sprites across restarts.
- Make tile viewer selection XOR with the background colour too.
- Dragging and dropping palette colours (should affect the colours of sprites too? This would allow for converting sprites from one palette to another).
- Proper error handling for encountering the end of a mappings file unexpectedly.
- SonMapEd doesn't ask to overwrite files.
- Add licence information to each source file.
- See suggestions in the Sonic Retro thread.
- Orient tiles vertically.
- Make duplicate sprites and DPLCs share data (make offset table entries point to the same data).