math syntax highlighting

[Jose Guilherme Vanz]

Hi

I started to work on the math syntax highlighting. Actually, I can 
identify when we have some problems with parenthesis  without close and 
etc. Now, I would like to change the color or background color to show 
to the user the problematic character. How can I change the color of the 
string? Is there some field in the OUString that can I do that?

Thank you