Mystery Media Control Button in iTunes Skin

There is a button to the right of the eject button on the iTunes skin in Media Control 4.0. It looks like it is supposed to open some kind of menu, but does nothing when pressed. I dug into the .ini file for the skin and it has command=*playlist
Is this button not yet implemented? Would it be possible to open the media library instead of the playlist?
Also, in the changelog for the media control, it says:
"Added playlist popup menu"
I'm assuming this is the mystery button. Please help. Thanks!

BTW,
TLB 4.0
Media Control 3.0
Winamp 5.03c
Windows XP Pro

Currently Media Control does not support playlist for Winamp

I think that I previously asked for this, but is there anyway to reassign this button to show winamp?

OK, it will show winamp, in the next version.