Just tested this, confirmed. /gmroll shows up on "player" window if logged into the game twice. Applies to production and dev server. /gmroll, as I understand it, shows the roll to both you (as the player) and the GM. It's probably doing it based on the user name of the player...and since you are still the same person in both windows it is showing the roll to both of you. Probably not intended but I don't think playing the game with two windows open on the same account is officially supported right now. Most people in F2F games use two accounts, a GM account and a game account, with two computers...that way the "player" computer can have a mouse that can be passed to the players and the GM has their own controls. With the way you have it set up the GM has to control everything or give up control while the players act which sounds like a pain to me (but is entirely dependent on how your group plays...I'd get annoyed in a RL F2F game if the GM moved all the physical pieces too but to each their own). Probably not super high priority since I don't think it's an intended use of the "Re-Join as Player" function. You may just have to use a 3rd party dice roller for your computer or phone specifically for GM rolls until (or if) this gets changed. Good luck!