How to change the foreground color?

[waylaa]

I have an application with an option to toggle between light and dark theme. The problem is that i haven't found a way to change the foreground color of the text in the logger. For example, when light theme is enabled, the text should become black and when dark theme is enabled, the text should become white. I tried changing the foreground property of the richtextbox but that didn't change anything.