I have a folder in my dock full of aliases to applications. When I add a new alias, the icon doesn't usually show up in the Dock folder:
but the icons are there in the Finder window for the same folder in every case. Usually the icons will show up eventually (with no clear indication of what triggers the fix), but these 4 apps have been stuck without an icon for some time and through a reboot. I have this now on Mountain Lion, but the same thing happened in Lion.
Does anyone know how to fix things (preventative or remedial) so the Dock will display icons properly?