Cant see all of the window you are moving but from what I see here it looks like you are moving the actual window position in an dout, not the locastion of the window on the track itself. So fdrustrating when we are not sitting side by side at the same computer!
I will go re-check in Sonar.
O.K. MY cakewalk by Bandlab windows look and act nothing like yours.
It looks like you are instantiating OS windows with the notation editor in them & then moving the whole window left or right.
Headscratch moment here.
MY notation editor is already in a separate Cakewalk window & can indeed be scrolled along by using the gadget at the bottom of the window. Exactly as I can do in Reaper.
I will figure out doing a screen shot if I can.
O.K. I just opened the same project in Cakewalk and Reaper. In Notation view, BOTH programs operate in the same way.
At the bottom of the notation view, there is a scrolling handle that enables you to scroll left or right through the track.
I can`t see the bottom of your notation window in your first screenshot, but if you look, you will see a scroll tool or handle that enables you to grab it and scroll back and forth through the track.
As I said in the beginning, the mistake you are making is trying to use the parent OS window to scroll, not the actual program.
You appear to be doing the same in Cakewalk, FWIW.
Might be worth revisiting some of Kenny Gioia`s free videos to actually watch someone editing notation. Hard to explain in words & like I said I havent ever done a screen shot "movie".