Highlighting of compositor nodes? How to use it? Checkbox in compositor's N-key panel is enabled, but I see no difference in behaviour.

My PC is Win7 64 bit, 4gb RAM, card ATI HD4670 500mb.

Anyway, assuming it is working, what information can I get from it? Collateral indication of nodes' memory consumption? For example, nodes which will be firstly highlighted are less memory consumption and so on.
From the Blender Bug Tracker: 


  This feature was disabled in the code but not in the interface.