[BUG] 0.952 - Trading tech knowledge can't be undone if trading all of a type

When trading tech knowledge with another kingdom, I offered to trade all of my military tech knowledge for all of their magic tech knowledge. It turned out that my 79 was worth considerably more than their 60, so I wanted to undo it. However, since the tech knowledge had 0 left, I didn't get the pop up to adjust it. I couldn't remove the tech from the display at all.

My only option was to restart the trade entirely.