Show Desktop NOT Toggle Desktop

A beer for the person who can explain to me how to change the default behaviour of the "Show Desktop" button!
At present, I regularly have to press it twice just to actually show the desktop, as it's default behaviour appears to be some not quite the same as for example the Windows behaviour.

I've searched around a bit and it certainly doesn't seem to be a new issue. There is a bug dating back to 2007 in Compiz bugzilla were two devs are discussing it, but it's not clear from it what the resolution was:

https://bugs.launchpad.net/ubuntu/+source/gnome-panel/+bug/236376

Many thanks to any one who can help me with this one.