I want to create a GUI builder program for 3DGS applications. And why do i don't use Qt, if it is so simple?

This time i have only one problem, i got the message: Error E1241: Can't open DirectX device,
when i try to bind the engine to a widget on the Qt window.

I'm afraid the answer will not be so quick, this topic is visited no so frequently.

Anyway thanks for your interest and help.

Playing a bit with the code, the error was eliminated.
But now, i can't close the engine with engine_close().
After the closing engine_status gives back 0, that means it is closed.
But i can see it in the tasklist in task manager.
What could be the reason?