Ok, this is getting to be a little bit too much...
(I've now got F1 on the Alphatrack set to 'Save' the project whenever I modify any thing so that I don't lose a half an hour's work all the time.')
I'm noticing that in certain cases, when scrolling horizontally in *either* the track view or the piano roll, that X2 simply crashes. In the case of the track view, it's when working on a midi track *and* you set its view to 'notes'. The crash is not instantaneous, it only happens when you then start scrolling.
I had it happen to me in the track view in several places where I was converting midi CC's to automation - it requires that you have the note view selected.
In the piano roll view, I needed to find an errant note that was wrongly triggering a key-switch in Aria. Easy enough to do in piano roll if you set the horizontal view of the PRV to show only the the out-of-range keys and than left-scroll to see what shows up. Works well, assuming X2 doesn't go boom-boom....
So, at first glance it appears to be piano roll/note roll view related...
Pipe up if you see this behavior (or are aware if this is already a known issue).