First of all a big Welcome to the forum, Felix!
I’m not an expert on MainUI yet, just starting to figure out the bits and pieces, but my idea would be set the cell to ‘highlighted’ and use the color property for highlighting.
Might work, but I’m not able to test it at the moment.
Don’t know if there is a property for the background color, but I would expect so.
Regards
Thomas
Edit: There seems to be a property ‘background’ that can be set, just found it reading this thread