Transparent Middle Mouse AutoScroller Firefox
 

This is rather trivial but I'm just curious to see if there's a config setting I've missed. When you middle click in firefox, the autoscroll icon appears and depending on your pointer location the page scrolls up or down. On Windows, this icon is transparent, however on linux, when the icon appears, it is opaque and has an awkward drop shadow. This doesn't affect functionality at all, just wondering if there is a visual tweak to change this. Digging into the theme files, I found the png that has the icon, and it is transparent.