> But I would like to the window  looked as in Windows XP. On the window have 
> been  buttons: Minimize, Maximize and Exit. How to do it? In QNX6.5 through -
> qws it all works.

QWS was a part of Qt 4.x that tried to be a Window manager "inside" a Qt application. By nature, a Window manager should
 not be part of an application itself, instead it should be over and above the applications it manages. With Qt 5, the 
Qt folks decided to discontinue QWS, because it was a weird design (IMHO) and because most supported Operating Systems 
have their own window manager.

QNX has "screen", which claims to be a window manager, but the understanding of the term "window" in QNX is different 
from rest of the world. You can have individual target "framebuffers" for each application, which can result in a kind 
of "window" but without a frame and without minimize or close buttons. BlackBerry has built a kind of window management 
on top of that, with apps being able to zoom and with a small area below the app to close it. But that's not part of QNX
 "screen", AFAIK.

With QNX's strong focus on Automotive and BlackBerry, most "apps" or use cases run in a full screen manner, anyway. The 
notion of having multiple "Windows" next to each other, with a "taskbar" to minimize them into, is very common only in 
very few use cases and as such probably has not been a priority at QNX R&D.

If you need to have multiple Qt apps next to each other on screen (?! of course I mean display), with the user being 
able to close or minimize them, or even drag them around, you have to implement this on your own or engage with QNX 
Services. I know it seems odd that a modern OS like QNX 6.6 cannot do what Windows 3.11 (and QNX 4.25) could do 
regarding Window management, but it is what it is. :)