EDIT: Figured it out—it was the Hider plugin, which I use to hide the ribbon. For some reason when the ribbon is hidden the sidebar panes can’t be rearranged. Thankfully I have this option mapped to a keystroke so it’s easy to turn the ribbon back on when I need to move the sidebar panes around.
I’m running Obsidian v0.12.12 on Mac. I noticed today that for some reason, when I try to drag my sidebar panes around to reorder them or have them sit next to each other as tabs, it won’t work. Clicking and dragging the icon of a pane should cause individual areas of the sidebar to highlight as “drop areas”, but instead the entire sidebar is highlighted and when I release whatever pane I’m trying to move it basically ends up as a solo pane in a random part of the sidebar.
The above screenshot shows what my right sidebar looks like now (although I’ve noticed the same problem affecting the left sidebar as well). Before this problem, the four lower panes—Backlinks, Longform, Tags, and Outline—used to be next to each other as tabs sitting in the lower half of the right sidebar. Actually, Longform used to be a tab in the left sidebar alongside Starred and Search, but now I can’t even drag it back up next to those.
I’ve tried turning off my custom theme, which didn’t help.
Anyone have any clue what’s going on here or how to fix it? Much appreciated.