Well it's pretty late when I write this, so sorry if this has been mentioned.
Force of will has two condition required for the stack, one is to pay life, second is to exile a blue card from your hand. If there is a proper blue card in your hand, the ui will ask you to discard. If you do not have a blue card however, no blue card is needed to be exile for force of will to be on the stack.
Also, when you selected the cards in your hand to be discarded/put back in your deck. Is there anyway to cancel those selection if I change my mind?
Overall, despite it's faults, this software is pretty amazing.

for those who helped making it.