Yeah, when DPC+ support gets implemented, it will have support for multicolored sprites
Nice, thanks! Also found another issue. I was trying to make my new game (GD2600, essentially a port of GD for the VCS) and sometimes when I just moved around the <div> placing block board, the sprites' frames were reset to default and the backgrounds auto-deleted themselves, only remaining the default background. But the code (thankfully) didn't get deleted along with everything else. But I think you should also fix this issue.
Okay, I opened the issue to look on that later:
https://github.com/haroldo-ok/vcs-game-maker/issues/135