xcode code completion - no arguments?

I am attempting to move my cocos-2dx development over to Xcode from Visual Studio. When using the -> or . operator on objects and I hit the Escape key to get the suggestion/completion dialog box, I can see all of the methods that the object can execute, but none of the methods show the arguments. For example, if I have an object of the CCLayer type called _layer, when I type “_layer->” I can see “addChild” but not “addChild(CCSprite)”. Has anybody else had this problem?