2021 and still Windows 7 UI?

[Sergio Miranda 2]

When project window gets minimized you can see old Windows 7 User Interface graphics.
I think it's about time to get rid of it, don't you?

Edited January 20 by Sergio Miranda

[Kevin Perry 406]

Which bits exactly?

[scook 2,740]

You may want to update the theme.

It appears seriously out of date.

See 

and

for the parts the need to be updated for the theme to function properly.

Of course none of the updates are going to address the MS libraries you are asking to be updated. 

[Sergio Miranda 2]

Are you shure of that?
This is a print screen with Mercury theme. The old Windows 7 UI is still there.

[Colin Nicholls 404]

15 minutes ago, Sergio Miranda said:

When project window gets minimized you can see old Windows 7 User Interface graphics.
I think it's about time to get rid of it, don't you?

This isn't really a Cakewalk problem. MDI applications in Windows pretty much have to deal the hand that Windows deals them with respect to non-client areas.

[scook 2,740]

8 minutes ago, Sergio Miranda said:

Are you shure of that?
This is a print screen with Mercury theme. The old Windows 7 UI is still there.

Absolutely, as I alluded to and @Colin Nicholls clarified, the objectionable part of the UI you mention is part of a Microsoft library.  

The theme in the OP, on the other hand, is a functional problem. Parts of the program don't work with that old user theme.

[Will_Kaydo 217]

9 hours ago, Sergio Miranda said:

When project window gets minimized you can see old Windows 7 User Interface graphics.
I think it's about time to get rid of it, don't you?

Not Cakewalk doing this, but your computer.

It optimizes for best performances itself. You have to turn the option off manually in settings.