I know that this can be controlled at the system level, but I want to override the system setting and have a certain appearance for only my application. I’m assuming there must be a Windows API function to control this because I’ve seen another windows app that does it.
(It is not necessary to go into the reasons why I should not do this)
If you want a custom appearance for your application, I would just make my form borderless and handle everything myself, either by drawing on the form itself in the Paint event, or else moving controls around (panels etc.) in the Resize event. You have to handle things like dragging, resizing, closing/minimizing etc., but none of this is especially difficult.
Here is my answer to a similar question, which shows the basics of doing it yourself (it’s for windows mobile, but it will work in regular windows too).