When I try to select many rows of a spreadsheet by selecting the bottom row, holding down the Shift key, and scrolling up using either PgUp or the Up Arrow key, the program takes over and continues to scroll itself up. Nothing I try stops it. I have to wait for it to get to the top, and it’s pretty slow.
Please try resetting the user profile, sometimes solves strange issues.
Usually it’s enough renaming/deleting the file “user/registrymodifications.xcu”, it affects all the options in Menu/Tools/Options, and the files “user/basic/dialog.xlc” and “scrip.xlc” are overwritten, additionally custom colors in “user/config/standard.soc” are lost.
I am encountering a similar behavior. See if the description at this link compares to what you are experiencing. A commenter here, m.a.riosv, suggested resetting the user profile. That is where I began, but without success. I have not been able to find anything that improves the situation as long as I stay with the current version. I think many people are posting about the same set of concerns, as seen from there vantage points. Being fragmented, the concern does not seem large enough. Maybe it’s a larger concern than it initially seems.