HaxeFlixel/flixel-docs — pull request #113 by ParamountSky (2014-11-16 02:50:01+00:00)
Title: Update 04-part-iii-groundwork.html.md

_btnPlay.screenCenter(); -> FlxSpriteUtil.screenCenter(_btnPlay);
in my case there is no method screenCenter() in _btnPlay object. But FlxSpriteUtil class has it.