Rather than having two fixed height scrollable divs beside each other, you should remove the fixed height on .content_scroller and fix the sidebar to the side with `display: fix`.
I think you mean `position: fixed` rather than `display: fix` right? In which case the side bar class .side_bar_column already has that. Unless you mean a different class/element?
Anyway looks like I'll have to attack this scroll issue a little more systematically. People usually complain about scrolljacking. I'm doing the absolute opposite, trying to let browsers do their thing themselves, but apparently that's bad too lol. Can't win.
In any case, there are a lot of reasons for scrolling the main document rather than having a subscroller, including:
1. Auto-hiding the address bar when scrolling down on mobile (it's not weird—all browsers do it) and pull-to-refresh in browsers that have it
2. Better accessibility because it doesn't break the PageUp/PageDown keys
3. Momentum scrolling
4. Better scrolling performance (higher framerate) because browsers optimise main document scrolling over subscrolling
5. Support for #fragment linking
6. etc.[0]
[0] https://nolanlawson.com/2018/11/18/scrolling-the-main-docume...
All your points have really convinced me to give document scrolling another go though. Thanks for the list and the link.