I have GM access to a game created by a friend. We are trying to learn the system together. I have created a two subfolders under characters, 1) for NPC 2) Monsters. However when I try and move the already created and populated character sheets into these subfolders, I cannot drag and drop them in. When I move the sheet by left clicking towards the subfolder I do get a broken lined rectangle appear, however pop up of a red circle ( in the UK this would described as a road sign giving an instruction) containing a red line slanting forward. I would describe this as a do not enter sign The Sheet was created by the other GM, but we both have edit and view access. What am I doing wrong?