See some discussion here:

https://github.com/phacility/phabricator/commit/24a6eeb8d8a52b592e456d110934670d4ace9b31#commitcomment-7334892

The protected $properties; storage parameter added to ProjectColumn is shadowed by getProperties() in the base class.

Although this works correctly for me, it's ambiguous and worth fixing. Make the base class methods explicit.

Used grep to find callers for both methods and renamed them.