Let's give this a shot. I'm not sure of all the info that you need, but I'll provide the situation, please let me know of any information that I am lacking.
Whenever I am in the Trading section of the app (not in the gathering), and I try to remove cards from the "give" section, the app immediately crashes. It has been doing so for some time now, but I normally just start a "new trade". However, when entering a large trade, I needed to remove just one card, but was unable due to this issue.
Please get back to me when you have the time, and maybe we can find (and hopefully solve) the problem (Be it something I can do, or something you can do).
Maybe?
I will look into it after I fix Drag & Drop.
Thank you, sir.