@sweth,
Sometimes things are more complex than expected. I've only gotten a couple of the issues figured out, but I want to record what I do have.
Horizontal Scroll Jump
Now that I've looked for it, I can see clicking a cell in one pane change the horz scroll in the other pane in ways I didn't expect, although not in quite the way you describe it. It happens when running with
calibre --ignore-plugins so it's not a plugin issue.
After a couple hours playing with it, I tracked down the cause. I've opened a
pull request that preserves the horz scroll positioning. Hopefully Kovid will accept it or come up with a better fix.
Add/Remove/Rename Views then Cancel vs Rebuild Menu
I think I've figured this out. But then I've thought that before.