Bidding button should contains the bidding price (screenshots to explain)
TL;DR: The bidding action is misleading on what price I bid on. I do not know if I bid on the displayed price, or the "incremented" price.
Having the price on the bidding button for instance, would help to see if it is worth it or not. Right clicking in the column between item/stack would also change the price on the bidding button.