I think I remember I came across some settings whereas the P3D window opened with the bottom taskbar visible and fixed there but still it was a full screen mode. I can't find it in Prepar3D.cfg nor in SIMstarter. Is it possilbe at all?

Thanks,

 

I'll using this program.  It works for FSX and P3D.

https://library.avsim.net/search.php?SearchTerm=pseudo+full+screen&CatID=root&Go=Search

 

Edit:  You may not be able to get to the task bar without going out of the pseudo mode.

Any negative sides with it, like some performance hit or VAS usage?

Thanks,

No side effects.  With FSX I seemed to have problems in full screen mode that I don't having in the pseudo full screen mode and no frame rate hit.  I haven't seen any problems at all in P3Dv4.  I don't have a lot of time in P3Dv4 though.  There is this note in the library entry, "Autohotkey needs to be downloaded and installed first.".  I just tried that in FSX  and you can go in and out of the pseudo full screen mode using the Win+F11 keys.  I'll try it in P3Dv4 and check back.

Worked as advertised in P3Dv4 also. 

https://autohotkey.com/download/