102663 2012-11-19 01:43:46 -0800 [Shadow DOM]: Event listeners are invoked for events with the same target and relatedTarget 2012-12-06 03:00:26 -0800 1 1 1 Unclassified WebKit UI Events 528+ (Nightly build) Unspecified Unspecified RESOLVED WONTFIX P2 Normal --- 102681 103230 0 sgrekhov webkit-unassigned hayato morrita shinyak webcomponents-bugzilla oldest_to_newest 770486 0 sgrekhov 2012-11-19 01:43:46 -0800 According Shadow DOM specification (http://www.w3.org/TR/shadow-dom/#retargeting-related-target) "Event listeners must not be invoked on a DOM node for which the target and relatedTarget are the same.". But in fact it doesn't work. Please run the following example in Chrome (found in Chrome 23.0.1271.64 m): <html> <head> <script type="text/javascript"> function test() { var d = document; var SR = window.ShadowRoot || window.WebKitShadowRoot; //Shadow root to play with var s = new SR(d.querySelector('#host')); var div1 = d.createElement('div'); div1.setAttribute('style', 'height:50%; width:100%'); div1.setAttribute('id', 'div1'); s.appendChild(div1); div1.addEventListener('mouseover', function(event) { console.log('div1:Event listeners shouldn\'t be invoked if target and relatedTarget are the same'); }, false); d.body.addEventListener('mouseover', function(event) { console.log('body:Event listeners shouldn\'t be invoked if target and relatedTarget are the same'); }, false); var evt = document.createEvent("MouseEvents"); evt.initMouseEvent("mouseover", true, false, window, 0, 10, 10, 10, 10, false, false, false, false, 0, div1); div1.dispatchEvent(evt); } </script> </head> <body onload="test()"> <div id="host"> </div> </body> </html> Observe JavaScript console. As you can see bot event listeners for div1 and body are invoked thorough event target and related target (see the last argument of initMouseEvent()) are the same (div1 for both) 784805 1 hayato 2012-12-06 03:00:26 -0800 Bug is filed for the Shadow DOM spec. https://www.w3.org/Bugs/Public/show_bug.cgi?id=20017 The current behavior is okay. Let me close this.