Hmm, I don't see this behavior either. I can simultaneously drag a token and pan the map with my mouse wheel. A super low probability thing: mouse wheel when pressing "E" on the keyboard is a hotkey for rotating a token. If I drag while pressing "E" and try to use the mouse wheel, I do get the behavior you described. Don't suppose you have a sticky "E" key on your keyboard? Longshot. With a token selected but not actively dragging, does the mouse wheel allow panning or does it still rotate?