Using sheet DnD 5E by Roll20 I use a sheet as a template for monster (npc) with a generic token image and populated abilities used as macros. This template is copied as needed when new monsters are added to the campaign. GM notes are added, stats are entered and the abilities/actions are updated. I've observed an error when the copied template sheet is modified and will not close the character sheet. I have found that if you make all of the changed but do not remove the avatar image, the sheet will close without issue. If the sheet is modified and remove the avatar in the same process, the sheet will not close and will only minimize. The only way to close the sheet is to refresh the window or restart the game. The page will not respond to any clicks when it has become frozen. The clickable tabs become discolored when they are hovered over but nothing happens when the tabs are clicked. Edit for more observations added.