User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:88.0) Gecko/20100101 Firefox/88.0

Steps to reproduce:

Place a basic button over video PiP toggle. Click the button over the area where it overlaps with PiP toggle.

Actual results:

PiP is activated.

Expected results:

The button click event handler should be called. PiP should not be activated.

Happens on both Windows and macOS 11, both using Firefox 88.0.1.

The Bugbug bot thinks this bug should belong to the 'Toolkit::Video/Audio Controls' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

I looked for a dupe in the dependency tree of bug 1519885 but didn't find any dupes, though I expect this is already on file.

Hey emilio, are the non-native widgets somehow special here? We seem to not consider the button when doing the nodesFromRect with aOnlyVisible...

Hmm, does this work with the native theme? I think the reason it doesn't quite work is that we don't know the opacity of the widget until it's painted, so perhaps we're not considering them opaque...

If that's the case, we could try to fix it by adding some sort of API to nsITheme to get a more exact opaque region in here.

Just wanted to note that bug 712289 was marked as a duplicate of this. However, in 712289 the same thing happens with a <div> (and minimal transparency) and not a <button>. So it seems that either it should be unmarked as duplicate, or there's something else going on that is not specific to <button> or widgets.

I think bug 712289 is probably the wrong bug - that one is a JS engine bug. Did you mean a different bug?

Sorry, you're right, I meant bug 1712289.

It seems this is also reproducible with native widgets. Notably, setting appearance: none on the button with either native or non-native widgets causes the issue to go away.

Just fyi, I can still reproduce this and bug 1712289 on 91.0.2. This is an actual issue that affects our product and clients have complained. Is there a chance these will get patched anytime soon?