I really like the feature in Timanthes, where the C64 color constraint errors automatically are corrected or shown with a bright red color (you can choose the option between autocorrect or warning). Could this be possible to add this feature in Pro Motion? I use this feature a lot in Timanthes, and it’s much more intuitive for me than the one in Pro Motion, where I have to press ctrl+G to check for errors.
Optimization idea from a non-coder:
If PM was to check each frame for errors (in this case, C64 multicol mode restrictions, etc) in real-time, using “tiles” may be part of the solution.
Photoshop splits up the document it’s displaying into tiles (I think they’re 512x512) and stores them in the buffer as a static texture until they change, regardless of how many layers are contributing, and it only updates that changed tile in the buffer if the user does something to affect one of the tile’s pixels. Pretty sure it mipmaps these tiles, too - for different zoom levels.
PS does this for the purpose of optimizing display of the document, but PM might use the same basic concept to optimize error checking - slice up the frame into tiles or regions, and only re-check tiles that have a detected change. Rather than, on every check, run an algorithm on every 8x8 chunk of the frame, or whatever the restriction criteria may be.
tiles ftw?
A bit too technical for me 
Are you saying that tiles in Pro Motion can do this today? I rarely use animations, so I only need the feature on single frames. And I have no idea why you mention Photoshop? 
Please explain, how I can set this up using tiles in Pro Motion, if that’s what you think is the solutuion.
No, I’m not saying Pro Motion does this currently. Just an idea to enhance performance should PM ever implement real-time checking.
I described Photoshop’s buffer tiles because it’s a similar concept.
I too can add this to my wanted list. I am using Pixcen today and I feel I need something more capable with animations etc and this might be it. But I will for sure miss the real time color constrains checking that Pixcen has. It saves so much time. Working this way is too slow, unintuitive and it makes it hard to find good solutions with cramming in the colors in each char.
So is it possible to add this in a future release?
Is on my list, but no ETA, yet.