Comment 58 for bug 193141

part of the problem is here:

        canDrop: function VO_canDrop(index, orientation) {
          var result = this._self.getResult();
          var resultview = this._self.getResultView();
          var node = index != -1 ? resultview.nodeForTreeIndex(index) : result.root;

          if (orientation == NHRVO.DROP_ON) {
            // The user cannot drop an item into itself or a read-only container
            var droppingOnSelf =
                this._getSourceView() == this._self &&
                this._self.view.selection.isSelected(index);
            if (droppingOnSelf || PlacesUtils.nodeIsReadOnly(node)
              return false;
          }

I think that we need to make this:

return droppingOnSelf || PlacesUtils.nodeIsReadOnly(node);

If we are dropping on, and not on ourselves and the node is not readonly, we should allow it.

This allows us to dnd from the right hand pane into "drop able" targets in the left. (Note, tags should not allow us to drag onto it, that will be a follow up bug.)

I still need to get dnd to work within the right hand pane.