aw_muench please have a look at the documentation for the INQUIRE statement.

Format 1 - bullet 8: 

The SYSTEM HANDLE phrase retrieves the host graphical system's handle that corresponds to the control and stores this value in system-handle....

That's the second step. But in order to "retrieve the host graphical system's handle that corresponds to the control" we need the cobol handle of that control. My problem is that the control (my window) was created in another program.

So my approach was somehow to get the cobol handle of the active window.

Or am I wrong ?