1529036 - Buttons don't receive mouse events from overflowing in-flow descendants

Status: RESOLVED FIXED

(Core :: Layout: Form Controls, defect)

Description

[Daniel Holbert [:dholbert]]

STR:

1. Load attached testcase
2. Click some of the text that's outside the button.

EXPECTED RESULTS:
Button should receive the click and an alert should appear.

ACTUAL RESULTS:
Button does not receive the click; nothing happens.

Chrome gives EXPECTED RESULTS.
Firefox Nightly 67.0a1 (2019-02-19) gives ACTUAL RESULTS.

(Note: if I make the overflowing content 'position:absolute', then I get EXPECTED RESULTS -- at least, I do as of bug 1089326 which fixed this case for abspos stuff.)

I think this may've been something that we overlooked in bug 1089326's fix (unless this was a case that we intentionally exempted for some reason?)

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: testcase 1: in-flow descendants' overflowing area isn't clickable

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: testcase 2: overflowing relatively-positioned descendant isn't clickable

The same thing happens if I make a descendant overflow by relatively positioning it -- the button doesn't receive its click events.

(Though if I absolutely position it, then the button does receive click events. Attachment 8946239 [details] is a larger testcase that shows the difference between those two behaviors.)

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

Sounds like some hit testing issue then. It is using display list creation.

Comment 4

[Olli Pettay [:smaug][[e-mail]]]

I guess https://searchfox.org/mozilla-central/rev/dc0adc07db3df9431a0876156f50c65d580010cb/layout/forms/nsHTMLButtonControlFrame.cpp#82-92

Comment 5

[Emilio Cobos Álvarez (:emilio)]

Yeah, looks like that was introduced in bug 1111995. Mats, would making the button anon box inherit border-radius be a better solution instead of clipping?

Comment 6

[Emilio Cobos Álvarez (:emilio)]

Hmm, though maybe that's not all, bug 770106 also looks relevant.

Comment 7

[Mats Palmgren (inactive)]

This should do it I guess:
https://treeherder.mozilla.org/#/jobs?repo=try&revision=6a37bcb38e4930d855d32709e30bc29c3f4d5218

Comment 8

[Mats Palmgren (inactive)]

Attachment: fix+test

Comment 9

[Emilio Cobos Álvarez (:emilio)]

Comment on attachment 9046278 [details] [diff] [review]
fix+test

Review of attachment 9046278 [details] [diff] [review]:
-----------------------------------------------------------------

Makes sense, thanks for fixing this :)

::: layout/forms/test/test_bug1529036.html
@@ +28,5 @@
> +      e.addEventListener('click', function(event) {
> +        ++clicks;
> +      });
> +    }
> +    

nit: Whitespace.

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/f36ad4139437
Clip <button> to its border area for event hit testing, but not its children.  r=emilio

Comment 11

[Stefan Hindli [:stefan_hindli]]

https://hg.mozilla.org/mozilla-central/rev/f36ad4139437