Switch "I Want" and "I have" in currency exchange

Please let us switch the items in the "I want" and "I have" so I don't have to switch the item in one slot to a totally different item before I can place it in the "I have" slot.

For example, just place a button in the middle which switches the places of the "I want" and "I have" items.

Ctrl + left click on one of the currency if I remember correctly from my muscle memory