Help on "regular expressions" in syntax definition files

[alex]

that is very difficult to implement.
Because contrast ratio is calculated dynamically when drawing, based on current background color and text color.
And because layering of styles with color transparency, it is very difficult to predict end result.
You can have read-only background, selection, highlights, embedded languages or nested levels in same time.
I can check for all styles and standard window color, but this will be partial solution and significant efforts.
So, I understand the problem, but will wait with such check until see that it is bothering a lot of people.