In early versions of EasyEDA, the "D" key was used to Detach a Schematic Symbol (and I think, a PCB Footprint) to allow it to be moved without dragging the nets with it. This was useful when swapping sub-parts in the schematic to optimise routing on the PCB because the sub-parts could be moved about without changing their prefix. Now the only option appears to be to Cut then Paste and the problem with this is that pasting the item changes the prefix. This is very inefficient when moving sub-parts because the original prefix and the sub-part number has to be remembered so that they can be changed back to the original part but the new sub-part assignments.