Saving a Theme in Mission Planner?

I have MP version 1.3.24 build 1.1.5574.33902 installed, and want to simply customize settings in MP itself. I got to the Config/Tuning / Planner section. No flight controller attached, just straight MP.

If I try to select the Them: HighContrast, nothing seems to change. I cannot find a button to SAVE the settings on this page. I guess it could be there but I am not seeing it.

Thanks for pointing me in the right direction to save values I select on this page.