Enable the auto compare setting (or hold ctrl).
Move the mouse over a shield in the store while having a 2 handed weapon equipped.
Expected: The shield is compared to nothing because you have no shield equipped.
Actual: The shield is compared to your equipped 2 handed weapon, these are not comparable items so the output is useless.
You might think this could be intended behaviour, but I don’t think it is because if you compare items with the auto compare setting off and just press ctrl instead then the shield is not compared to the 2 handed weapon.