Title Bar background color issue

Hi everyone. I’ve searched the community about how to change the Title bar background color. I found some related topics but can’t find any solution to it. As there’s no option to chance its color in the Properties Tab, how can that be aplied? I tried: When screen 1 initialize > do set screen 1 Title bar color to … and it doesn’t work. I appreciate any kind of help.

In screen1. Title bar color block is there u can use that.