How to create GUI Frame mask

I want to create a mask-type frame that masks other frame, Such as The Frame is black but when I create a mask that blocks that background frame, it allows to see through allowed mask area. Just like we do In any photo editing software, Is there any way to do it?

1 Like

Do you have example photos and also how is it set up in your explorer window and what are the properties you are using on the gui frame?

Actually I am asking about a solution on how I Mask over another frame, I currently have no Idea How it is done.