User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:34.0) Gecko/20100101 Firefox/34.0 (Beta/Release) Build ID: 20140807030202 Steps to reproduce: 1. Navigate to test case on jsbin. http://jsbin.com/qutugoli/1 2. Open console. 3. Click on the yellow canvas element inside the button. Actual results: In Firefox the mousedown and mouseup event callbacks are never fired. In Chrome and Safari the mousedown, mouseup, and click callbacks are fired. A secondary concern with this is related to touch events. When simulating touch events no touchstart or touchend callback is fired on the canvas element, only the click on the button. Expected results: I expect the mousedown and mouseup events to be fired.

I did a quick follow up test by wrapping the children of the button in a div to see if the workaround for flexbox layout on button’s would cover this use case as well (https://bugzilla.mozilla.org/show_bug.cgi?id=984869#c2). This workaround did not solve the problem.

Confirmed 34.0a1 (2014-08-07), Win 7 x64