Bug 239946 – [css-overflow] an element's scrolling area must include the margin bottom of its last descendant

• Component: CSS
• Status: NEW

[Gérard Talbot (no longer involved)]

Description
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The bottom edge of an element's scrolling area is the bottom margin edge of all of the element's descendants boxes. Therefore, an element's scrolling area height must include the margin bottom of its last descendant.


Tests
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WPT Test:
http://wpt.live/css/css-overflow/margin-block-end-scroll-area-001.html


Reference:
http://wpt.live/css/css-overflow/reference/ref-if-there-is-no-red.xht


Test results:
https://wpt.fyi/results/css/css-overflow/margin-block-end-scroll-area-001.html?label=master

https://wpt.fyi/results/css/css-overflow/margin-block-end-scroll-area-001.html?label=experimental


Blink equivalent bug report:
https://bugs.chromium.org/p/chromium/issues/detail?id=750992


The test fails with Epiphany 3.38.2 (WebKitGTK 2.36.0).

A green-versus-red variation of the test above:

http://www.gtalbot.org/BrowserBugsSection/CSS3LogicalProps/margin-block-end-scroll-area-002.html


Related specs
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2.2 Scrollable Overflow
https://www.w3.org/TR/css-overflow-3/#scrollable

6. Extensions to the Element Interface; scrollTop attribute
https://www.w3.org/TR/cssom-view-1/#dom-element-scrolltop

Scrolling area definition
https://www.w3.org/TR/cssom-view-1/#scrolling-area

[Radar WebKit Bug Importer]

<rdar://problem/92928629>