concrete5/concrete5 — pull request #1152 by mkly (2013-07-11 00:31:16+00:00)
Title: Fix Date Nav Add/Edit Block Error

Fix date nav add/edit block error

- `value` was `undefined` but compared in conditional
- Check for `undefined` before comparing

http://www.concrete5.org/developers/bugs/5-6-1-2/error-after-adding-datenav/