Dragging items is crucial when you have multiple tabs in MIR 3D (i.e. several halls, or several versions of the same hall with different settings). You'll drag the selected instruments to another "headline" in the list then. (see attachment). Just try it! Creating a new tab is as easy as clicking the "+"-sign in the right of the displayed Venue name on top of the map.
... dragging items to the map itself will do nothing, though. 😊
HTH,
MIR3D_MovingIconsBetweenTabs.gif-1696259709968-l82jc.gif/Dietz - Vienna Symphonic Library