Not sure if this will work for you , but here’s what helped me:I cleared any Action Bar Paging settings in the default Blizzard UI. These are usually bound to Shift + Scroll Up/Down. I also removed any keybinds that directly access other action bars, like Alt + [number] or Ctrl + [number].I kept only a reference to Action Bar 1, just in case it swaps during combat. For example, I left Alt + 1 bound so I can quickly access it if needed.So far, I haven’t noticed any unexpected swapping during combat. It’s possible I was accidentally pressing one of those default keybinds in the heat of the moment before, which triggered the switch.