onClick listener doesn't work on iPad

Steps to Reproduce

<image src="/image/X.png" height="100px" width="200px" onClick="self.detach()"/>

1. load the zul above with iPad
   iPad 3(The New iPad), iOS 6.1.3, safari
   iPad Air, iOS 10.0.2, safari/ chrome
   iPad, iOS 5, safari
2. click the image

Current Result

no effect, the image still exists

Expected Result

ZK invokes the onClick listener.

Debug Info

1. chrome device simulator can't reproduce it
2. a button's listener works correctly. But other components without cursor:pointer have this issue, so it affects lots of components.
3. 8.0.4.2 CE doesn't have such issue. only EE has this issue.
4. register the touchstart event (https://developer.mozilla.org/en-US/docs/Web/Events/touchstart) instead of click event might solve this problem in an architectural way.

Root cause

an iPad safari bug, No event bubbling without a cursor style, ref: http://www.shdon.com/blog/2013/06/07/why-your-click-events-don-t-work-on-mobile-safari

Workaround

• .z-image { cursor: pointer }