Possible reason why sometimes the layout gets corrupted and won't let you scroll/pan normally

Does anyone know of a possible reason why sometimes the layout gets very hard to work with (scrolling / or pg_up/pg_down is laggy or computer has to “think” very much before letting you scroll again)? My problem is scroll related only.

Photo

If you don’t know of any situation, please don’t post a reply. Thank you.


EDIT:

The workaround for me was:
- To create a new MIDI track and draw a MIDI part
- Open that part in the score editor
- Export the layout (Scores > Settings > Layout > Functions > Export)
- Import the exported layout to the corrupted layout
Result: Cubase didn’t crash anymore, and scrolling worked normally once again.