We didn't stay there for more than 3 minutes, but it did not while we were waiting.

Okay, that's a pretty long light and I would guess that it might have changed to "Walk" after a couple more minutes. A lot of the pedestrian buttons are actually fakes, its too expensive for them to take out the buttons so they end up just leaving them. someone should investigate and make sure that it actually changes to "walk" eventually

http://www.todayifoundout.com/index.php/2012/07/many-crosswalk-signal-buttons-dont-do-anything-anymore/

Just wanted to add that I also noticed this today. South side of Michigan Ave.