Make a panel outside the window of the engine

Hi everyone!

me and my friends are building a game that its purpose is to make for our battle in a role playing game a visual asspect.
one of our friends said it will be dufficult and not convenient every time he want to edit a foe to close the game window so we will not see it and then update it and resume the fight.
my question is there any way to open a new window that will affect the other window (like two diffrent windows of chrome) that can comunicate with each other? i want it to have editing privilage that will effect the battlefield like healing or a place when he can see the health of our foes without us knowing in what state the enemy is.

Thank you for your answears! (btw first question! :slight_smile: )