User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:53.0) Gecko/20100101 Firefox/53.0 Build ID: 20161127030208 Steps to reproduce: https://jsfiddle.net/48L8sky4/ To test with nightly, the bug is not present in other releases (or aurora maybe, didn't tested). Click on the select button. Actual results: The drop down shows but the onclick event is not triggered unless we click a second time to close it. Expected results: It should trigger on opening and a second time on closing. mousedown and mouseup are also bugged in a similar fashion, they trigger only once, though mousedown does it before the dropdown.

I've updated the fiddle because the alert was stupid. https://jsfiddle.net/48L8sky4/2/

[Tracking Requested - why for this release]:

Regression window: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=a925f48bcc829d19b1c9f35d15c5a5f03b23b91c&tochange=aba885aafee0210b1f063a423b1c0b3ce28d15f7 Suspect: Bug 1311279

Via local build, Last Good: 23ec12a251ee First Bad: aba885aafee0 Regressed by: aba885aafee0 Neil Deakin — Bug 1311279, scroll the select popup when click+drag is used, r=mconley

And not only click event, but also mouseup does not fire at 1st click mousedown does not fire at 2nd click

Tracking 53+ to address this select regression.

I'm not really sure what is a good way to fix this. The issue is that we need to capture the mouse on the menupopup to be able to capture mouse movement for drag scrolling. This means that the mouseup will get targeted at the menupopup and not propagate down to the child process. In non-e10s the capture occurs on the <select> element so it can receive the mouseup/click. One note is that in non-e10s, if you click, hold and mouse the mouse elsewhere and release, a mouseup still fires at the <select>, unlike with other elements. Interestingly, Chrome on Mac fires the mouseup/click events even before you've even let go of the mouse.

Is this related to bug 1312867?

No.(In reply to Andrew Overholt [:overholt] from comment #8) > Is this related to bug 1312867? No, it is a regression from 1311279.

This bug is not reproducible on nightly after bug 1311279 was backed out.

Close per comment 10. Please feel free to reopen if I miss something.

Looks like this was fixed in 53 with the backout from bug 1311279.