I’m a newbie here and am trying to figure out how to make this work well for me. When I have been setting it up, somehow I can no longer resize or expand/collapse the sidebars. I have included a screenshot.
Well, I don’t know, maybe it’s your theme broke it, but in original theme you can move “backlinks”/“tags” tabs and set it like you do at screenshot, like split view with note. To make it expand/collapse, you have to move it tab to sidebar again. Just hold title of tab ("#"-tab) and move it to left sidebar.