My group are currently playing through the purchased module of Princes of the Apocalypse for 5e D&D. Usually I like to keep all potential combatants on the map, hiding on the GM layer, so they are ready for me to reveal to my players when required. It is sometimes required though to hastily grab something from the compendium to further the game. Last night during a particularly intense battle against one of the more unique and fearsome adversaries of this campaign, I discovered a very peculiar and critical issue. In this instance I had all the relevant combatants character sheets 'popped-out' into seperate windows, to leave the Roll20 focused as the primary window. I dragged and dropped a creature from the Compendium onto the battle map (object layer), of the primary window, all other sheet windows were minimized/unfocused. In this case the token for the new creature never loaded into the game, and instead the character sheet of the CL 19 antagonist for the module has been entirely overwritten by the information from this Compendium drag & drop, and short of recreating the module and potentially archiving/importing a 'fresh' version of the character sheet I see no way to recover. Is there a simpler and faster way to recover a unique sheet? If not a bug, how can I avoid this in future? What did I do wrong?