This script throws up a menu of the objects under the cursor for selection - similar to right-clicking Photoshop's move tool to select a layer.
-Select a single object by picking from the menu.
-Select multiple objects by holding down the control key while picking.
-Use 'All -' with or without the control key - to add/remove all listed objects from the selection.
This is best bound to a key - as it wouldn't be much use in a quad.
Installation: Unzip the file - then run the .mzp file from maxscript/run.