TBH I don't know if this is an add-on issue or a game UI issue but the Expansion Button has disappeared for me today (maybe earlier but I only noticed today). When I'm in edit mode I can see it and I can toggle the Hide option but no matter which setting I select it disappears once I get out of edit mode.

Yeah, it's back working today so either a conflicting add-on was updated or they fixed it during the weekly maintenance.

Noticing this too. Its there when I /reload, but soon as I enter Edit Mode it disappears.

Allright, narrowed it down to another addon having an outdated version of the EditModeExpanded library embedded. I've updated the one in Dragonriding Speedrun, but if theres any other addons that use it, they'll need to update it themselves.

Took me a while to figure out why its not showing during edit mode, turned out I just had it unchecked here: