I like transparency in panel 1. If I load a theme with that particular icon, then click the show desktop icon, the icon becomes transparent, and is no longer selectable. Maybe the png has a transparent background?The old and new themes are fully usable.
The theme I'm running now is an older one, A-SBlack Blue, because the show desktop icon is usable.
If a theme is not complete, automatically Enlightenment put the missing part the default theme.
In this particular case the problem is in the emodule deskshow.
The problem I think
, When upgrading is a mixture of legacy applications that do not go well with the new version.