Non-Transparent Macro Icons in 2010

I looked around but didn't find this discussed anywhere.  The custom macro icons I used in 2009 now have a white (instead of transparent) background in 2010.  A minor point, but if I go to the trouble of making icons, it would be nice to have them look right.  The icons in question are 24x24, but I get the same behavior with 16x16.

SolidworksUser Interface