Changing gadget styles?

I'm trying to make a GUI creation tool that will generate B+ code. I realize that there are many already available, but I want to put my own spin on that type of program. Anyways, I need to figure out how to change the styles of gadgets like windows without remaking them. Any Ideas?

BlitzUI works... I have not yet tried any of the other tools. BlitzUI (as far as I know in my limited opinion on this...) was designed for B3D but it do work well... I am gonna try some of the other GUI libs now!

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wrong post.
delete and nevermind