When you left click an item, you should be able to mouse over other items for the same gear slot to get the compare screen that tells you the stats/etc differences between the two items. This works as expected if you compare two shields while a Squire is the active char, but if you have another character instead it does not pull up the second window for the shield under your mouse and the compare screen.
Repro Chance: 100%
Steps for Bug Repro:
1) Select a non-Squire character, I chose an EV
2) Left click on a shield to make it the active item
3) Mouse over another shield
4) Observe nothing pops up :)
Expected Results: You should observe the second shield popping up, and the compare screen.
This seems to be the case for all items that are unequipable on the currently selected heroes. Although it's only occurring when both items are located in a bag.