When in the Test Play mode from the deck builder the following needs to be fixed:
1. Using the CTRL + U to untap cards it only works for the user on the bottom, even if the top deck/player is the active one (based on where the stage/steps are)
2. When you add a token creature and try to hit CTRL + C to copy it the copies always appear on the battlefield under the bottom user's battlefield, even if you need them at the top.