Resolve issue #193 - Gui Editor treeview now refreshes correctly when changed through a drag/drop operation.

Engine/source/gui/controls/guiTreeViewCtrl.cpp

@@ -3437,6 +3437,8 @@ void GuiTreeViewCtrl::onMouseUp(const GuiEvent &event)
       scrollVisible(newItem);
 
       onDragDropped_callback();
+
+      buildVisibleTree(false);
    }
 
    mDragMidPoint = NomDragMidPoint;