How to subordinate the main window of one program by bringing it into the main window of another?

Question

User interface

Have you encountered this problem and how did you solve it?
There are two independent programs. It is necessary that the window of one of them is inside the main window of the other. Those. combination of programs. And so that it was not clear to the user that these are two different programs.
What was used for this?
upd. Are there known issues when using SetParent ? Are there other ways?

Answer 1

GetWindow , SetParent .