Discovered this via a Tweet from mikeash:
Regain a little developer sanity in Lion: Sys Prefs->Language&Text->Text->Word Break->English (US, Computer). (ht @danielpunkass)
It’s not just in Lion tho. Seems that’s been around for a while.
So what does it do? From Apple’s help:
The English (United States, Computer) setting is for programmers who often use combined words, such as “aKey:aValue,” and want to highlight only a portion of the word when it’s double-clicked.
Ah yes. A programmer’s life was just made a little less frustrating. 🙂