This is a bug report. I reported the same on Github ( https://github.com/cocos2d/cocos2d-html5/issues/958 ).
Issue: when using cc.Director.setContentScaleFactor(), the touch position are not handled properly.
Steps to reproduce:
1/ Use renderMode:1 (Canvas only)
2/ Add a cc.Menu with some cc.MenuItem elements to the main layer
3/ Use the Hello World sample code which was available in 2.1.1 to resize the canvas depending on the size of the window
Result: the designs are properly scaled, but the touch positions are wrong
Expected result: the touch positions should be scaled properly (following the designs)
PS: it works fine on 2.1.1
Thanks and good luck!