The show desktop button does not work properly.
A gray veil appears instead of the selected image (see image below)
It works, and frankly, makes that (crazy small) button more usable with certain skins, but I was able to reproduce what Dave was noticing below, the transparency on hover:
I did report that to them when you and I were looking at your skin earlier. It was their Beta 2 feedback thread, Replies 43 and 44:
The rule for issue reporting is "Once is enough". Hopefully they'll get it fixed before too much longer.
I will log it - ty for the feedback.
Internal Ref: ODNT-4911
Stardock Product Lifecycle Manager