Volume Control: Cursor Size Problem

[roger]

Hi,

I've got a (small) issue regarding the size of the Volume Control plugin.
I currently run Xfce 4.0.6 with the panel being horizontal at the bottom of 
the screen, though actually I've been observing the following behavior since 
Xfce 4.0.0

If the "popup position" is set to "top" (little arrows above icons) or 
"bottom", the Volume Control's cursor will be significantly smaller than the 
progress bars of plugins such as systemload, diskperf and netload.
See	ftp://rmlx.dyndns.org/pub/misc/panel.jpg
However if the popup position is set to left or right, their sizes appear to 
be all the same.
This is regardless the theme used or the panel size.

However I lately saw another user's panel screenshot with a similar 
configuration but this size problem (or at least not so visible).
Any idea on what could be wrong with my own system?

Thanks,
Roger