So, FWIW, I can edit new Items, but existing Items (both in the sidebar and in character sheets) can't be edited - as in, there's no edit button, double-clicking everything does nothing, and the radial menu doesn't have it as an option.

However, newly-created Items don't have the little padlock, so they always display as if they're in "Edit" mode.

This is steadily becoming more of a problem as characters use/acquire gear.

No rush, just updating.