The dual weapon hotkeys work only on un-enchanted & un-improved weapons.
Soon as you enchant or improve them on the grindstone, any attempts to use a different item that is not two handed will have your dual weapon hotkey UNBIND itself repeatedly. This happens despite the fact that they are identical and stack in the inventory and quick menu.
It's keeping me from enjoying my dual wielding dagger rogue. I can only swap between dual daggers & bow. If i try to use anything else like healing spell, or shield i lose my daggers hotkey.
*bangs head against wall*