It is one of the most infuriating “features” in Cubase. It makes the simple acts of navigation and control adjustments a minefield. I have screwed up settings countless times because of this functionality.
What I’d like is to leftclick/drag over a control or data entry point. All the scroll wheel should do is operate the selected window’s miniscule scrollbars. The exception to the rule would doubleclicking on a data entry field (or even a GUI control to make it “hot”) …then the scrollwheel can be used for data entry without changing any window navigation until Enter or Return is invoked.