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Animations - as per below - and the fact you can drag potions (line 49) to a henchman to have them drink it is hardcoded. They also disappear on the last use even if they have charges or uses/day added, and the game assumes only one usable item property when dragging to the quickbar.
Flails
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and Morningstars
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Fails (light and heavy) and morningstars cannot be equipped in the off hand due to engine coding. They also never use the polearm "over the should at ease" rest animation, which Halberds and other polearms do, likely due to animations or clipping.
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