This is an interesting thought. I tend to use the top window more or less as headers – markers for song sections (and start and end of the mix), the chord track mostly for reference for when I’m arranging/tracking (so basically like a chord chart), and time signatures (only if they change over the course of the song). I’d prefer them being fixed, “headers”, kind of like in the case of a freeze panes thing in Excel, where you can still edit the cells above (and/or to the left in Excel) the freeze, but they maintain their size and position, and you don’t really have to worry about scrolling within the frozen areas.
I came to Cubase (starting around 9.5, though fully at 10.5) from Cakewalk SONAR, where there were only markers, not a marker track, and they were at the top, as part of the timeline if I’m remembering correctly. I think time signature changes also got displayed up there, though I don’t recall for certain. They didn’t have a chord track (at least at that point – the new version of SONAR has a lot of enhancements, but I only use it for checking file compatibility for stuff I’ve generated in Cubase).
I also do end up having the issue of accidentally scrolling in the top pane, and I keep it very narrow (e.g. no reference tracks up there, just the “header”-type tracks).
I don’t use it for reference tracks, and that’s mainly a vertical space issue – that’s the biggest thing I run out of in Cubase as it is. In fact, I keep reference tracks i a folder below the Stereo Out, with all except one disabled, going to Cue Sends, rather than the Stereo Out to make it easy to switch quickly between my mix and whichever reference track I’m using at the moment in Control Room.
I might actually prefer reference tracks to be in a separate pane that could be toggled open or closed since I tend to only need to access those when switching between reference tracks.
Just thinking out loud with respect to pinned tracks, I think I could see that working for the header-type uses. The split pane we have now doesn’t really make as much sense for those, even if it largely works (i.e. if we ignore scrolling frustrations).
I can also see potential uses for the split pane that I don’t use at all at this point, like if I want to see two tracks at once (e.g. MIDI for drums and whatever I’m working on at the moment), but those tracks are too far apart to conveniently see them without hiding a bunch of tracks in between. But maybe even that sort of thing could work with pinned tracks, as long as there aren’t too many pinned tracks taking up vertical space. That is one area where I can see how having the scrolling top pane could be useful, if wanting to see different things at different times up in that area.
In case it’s not obvious, most of my comments here are just “thinking out loud”.