Cocos2d-x 3.0 alpha: getContentSize return not right

resource folder:
resources-ipadhd
resources-ipad
resources-iphonehd
resources-iphone

i use iphone retina, it will load resources-iphonehd, but some time getContentSize return contentsize of “resources-iphone” and resources-ipad
Cocos2d: selected Button_Menu_Setting.png (176.000000, 64.000000)
Cocos2d: Button_Menu_Shop.png (704.000000, 256.000000)