diff --git a/layout/generic/StickyScrollContainer.cpp b/layout/generic/StickyScrollContainer.cpp index 2e9d32ab5fca..416bbbf4c4e3 100644 --- a/layout/generic/StickyScrollContainer.cpp +++ b/layout/generic/StickyScrollContainer.cpp @@ -186,12 +186,17 @@ void StickyScrollContainer::ComputeStickyLimits(nsIFrame* aFrame, // Containing block limits for the position of aFrame relative to its parent. // The margin box of the sticky element stays within the content box of the - // contaning-block element. + // containing-block element. if (cbFrame == scrolledFrame) { // cbFrame is the scrolledFrame, and it won't have continuations. Unlike the - // else clause, we consider scrollable overflow rect because and the union - // of its in-flow rects doesn't include the scrollable overflow area. + // else clause, we consider scrollable overflow rect because the union of + // its in-flow rects doesn't include the scrollable overflow area. We need + // to subtract the padding however, which _is_ included in the scrollable + // area, since we want the content box. + MOZ_ASSERT(cbFrame->GetUsedBorder() == nsMargin(), + "How did the ::-moz-scrolled-frame end up with border?"); *aContain = cbFrame->ScrollableOverflowRectRelativeToSelf(); + aContain->Deflate(cbFrame->GetUsedPadding()); nsLayoutUtils::TransformRect(cbFrame, aFrame->GetParent(), *aContain); } else { *aContain = nsLayoutUtils::GetAllInFlowRectsUnion( diff --git a/testing/web-platform/tests/css/css-position/sticky/position-sticky-padding-001-ref.html b/testing/web-platform/tests/css/css-position/sticky/position-sticky-padding-001-ref.html new file mode 100644 index 000000000000..efe584bc8854 --- /dev/null +++ b/testing/web-platform/tests/css/css-position/sticky/position-sticky-padding-001-ref.html @@ -0,0 +1,37 @@ + + + + +
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diff --git a/testing/web-platform/tests/css/css-position/sticky/position-sticky-padding-001.html b/testing/web-platform/tests/css/css-position/sticky/position-sticky-padding-001.html new file mode 100644 index 000000000000..6bd4952c28fe --- /dev/null +++ b/testing/web-platform/tests/css/css-position/sticky/position-sticky-padding-001.html @@ -0,0 +1,73 @@ + + + + + + + + + +
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diff --git a/testing/web-platform/tests/css/css-position/sticky/position-sticky-padding-002.html b/testing/web-platform/tests/css/css-position/sticky/position-sticky-padding-002.html new file mode 100644 index 000000000000..972288fd3a84 --- /dev/null +++ b/testing/web-platform/tests/css/css-position/sticky/position-sticky-padding-002.html @@ -0,0 +1,71 @@ + + + + + + + + + +
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