Chat window too dim to read

I have logged into a client computer and the chat window it too dim to read.  I tried popping the chat window out of the client display so I can read it on my second monitor.

I asked for support from another person and they logged onto the same client with me.  I cannot see their text in the pop out window, only in the client window and that is too dim.

how can I increase the brightness of the client window?