Verno wrote on Nov 17, 2011, 12:55:

I’m not sure why you all are having issues with it. I have two swords both with different enchantments. One with Ice the other with Fire and I’m having no issues at all with it. I haven’t tried an Axe. So I’m not sure about those. I switch back between the swords and my bow a lot and a heal spell. But, I have had some issues with other keys sometimes seemingly getting confused and not working until; I hit either TAB or escape and they work again.

Are they the same sword though? I think you're misunderstanding what people are wanting here, they want a single hotkey to equip different weapons for dual wielding purposes. Try equipping an axe and a sword to the same hotkey, you can't. Any items that are "grouped" under the favorites menu you can dual wield by hitting the same button twice. For example if I have 3 Imperial Swords and I assign hotkey 5 to them I can dual wield them by hitting 5 twice. Once equips one of those imperial swords in my right hand, a second time equips another in my left. Any items that aren't grouped can't be dual wielded without using two different hotkeys to select them. There is an annoying workaround involving having one previously equipped and switching hands but we're not counting that because its silly.

It's just a limitation of the system they chose unfortunately, the only way it'll be fixed is likely through mods.