I'm seeing a similar issue to the one reported by mr_vico.
Upgraded from 6.02 to 6.20. Some Desktop Context menus no longer work (an empty sub-menu appears when they are selected).
Under 6.20:

This is the way the menu that appears under 6.02 with Fences enabled and Under 6.20 with the Fences context disabled (Computer\HKEY_CLASSES_ROOT\Directory\background\ShellEx\ContextMenuHandlers\FencesShellExt)

It also happens with Power Options and Switch Power Plans menus.
Let me know what other information I can provide to troubleshoot this.