Windows Explorer issue

Some programs start up with the program window at the back, whereas at the front folder windows are open. Clicking on the program window at the back does not activate this window or bring it to the front. I have to close all folder windows at the front, before the program window can be activated and used.
As said, it is a minor annoyance, so I hope it is only a Windows setting, I overlooked. Maybe it is connected with using some older programs from the W7 period.
Windows 10 Pro 64 bit v20H2. Earlier versions than 20H2 did already have the same issue.

dalchina said:

Do you have any sort of 3rd party add-on or program that can set a window to be 'on top'?

This is a capability which is not exposed by the O/S but is made use of by many 3rd party programs, some of which add extra options or titlebar buttons for this and other functions.

Short answer: no
Long time ago (I nearly forgot) it was possible to have more than one windows explorer active (as visible in Task Manager).
I did something - I forgot how - that only one Explorer could be active.
Maybe it is connected with that.

Yeah, that was the solution.
I unchecked; Launch folder windows in a separate process.
Starting a program, the program window is now at the top and active.
Thanks!
Issue solved.