Why won't Special Characters display certain characters? When I access Special Characters (⌘+⌥+T), many groups of characters will not display any characters. Coptic, Glagolithic, Runic, Gothic, etc. (Mostly more obscure characters) I'm running OS X Lion.
First, you may need to enable these groups by clicking the button in the upper left and choosing "Customize List…":



Then find the desired list and check the checkbox:



If you have done this and you see boxes instead of characters, it just means you don't have a font that supports those characters. If you download and install an appropriate font you should start seeing the characters.