diff --git a/layout/generic/nsFrame.cpp b/layout/generic/nsFrame.cpp
index 5e80fc1b8a3d..321a5116826b 100644
--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -10967,8 +10967,9 @@ nsIFrame::IsStackingContext(EffectSet* aEffectSet,
{
return HasOpacity(aEffectSet) ||
IsTransformed(aStyleDisplay) ||
- aStyleDisplay->IsContainPaint() ||
- aStyleDisplay->IsContainLayout() ||
+ (IsFrameOfType(eSupportsContainLayoutAndPaint) &&
+ (aStyleDisplay->IsContainPaint() ||
+ aStyleDisplay->IsContainLayout())) ||
// strictly speaking, 'perspective' doesn't require visual atomicity,
// but the spec says it acts like the rest of these
ChildrenHavePerspective(aStyleDisplay) ||
diff --git a/layout/reftests/w3c-css/submitted/contain/contain-layout-ignored-cases-ib-split-001-ref.html b/layout/reftests/w3c-css/submitted/contain/contain-layout-ignored-cases-ib-split-001-ref.html
new file mode 100644
index 000000000000..eb787424ed47
--- /dev/null
+++ b/layout/reftests/w3c-css/submitted/contain/contain-layout-ignored-cases-ib-split-001-ref.html
@@ -0,0 +1,76 @@
+
+
+
+
+ CSS Reftest Reference
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/layout/reftests/w3c-css/submitted/contain/contain-layout-ignored-cases-ib-split-001.html b/layout/reftests/w3c-css/submitted/contain/contain-layout-ignored-cases-ib-split-001.html
new file mode 100644
index 000000000000..d9f976deb8ca
--- /dev/null
+++ b/layout/reftests/w3c-css/submitted/contain/contain-layout-ignored-cases-ib-split-001.html
@@ -0,0 +1,77 @@
+
+
+
+
+ CSS Test: 'contain: layout' should have no effect on non-atomic inline
+ (including its block part, if there's a block-in-inline split)
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/layout/reftests/w3c-css/submitted/contain/contain-paint-ignored-cases-ib-split-001-ref.html b/layout/reftests/w3c-css/submitted/contain/contain-paint-ignored-cases-ib-split-001-ref.html
new file mode 100644
index 000000000000..8a698b9d2ce2
--- /dev/null
+++ b/layout/reftests/w3c-css/submitted/contain/contain-paint-ignored-cases-ib-split-001-ref.html
@@ -0,0 +1,76 @@
+
+
+
+
+ CSS Reftest Reference
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/layout/reftests/w3c-css/submitted/contain/contain-paint-ignored-cases-ib-split-001.html b/layout/reftests/w3c-css/submitted/contain/contain-paint-ignored-cases-ib-split-001.html
new file mode 100644
index 000000000000..eb21a2d46095
--- /dev/null
+++ b/layout/reftests/w3c-css/submitted/contain/contain-paint-ignored-cases-ib-split-001.html
@@ -0,0 +1,77 @@
+
+
+
+
+ CSS Test: 'contain: paint' should have no effect on non-atomic inline
+ (including its block part, if there's a block-in-inline split)
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/layout/reftests/w3c-css/submitted/contain/reftest.list b/layout/reftests/w3c-css/submitted/contain/reftest.list
index c3836767cdab..069cbacd1450 100644
--- a/layout/reftests/w3c-css/submitted/contain/reftest.list
+++ b/layout/reftests/w3c-css/submitted/contain/reftest.list
@@ -10,6 +10,7 @@ pref(layout.css.overflow-clip-box.enabled,true) == contain-paint-clip-006.html c
== contain-paint-containing-block-fixed-001.html contain-paint-containing-block-fixed-001-ref.html
== contain-paint-formatting-context-float-001.html contain-paint-formatting-context-float-001-ref.html
== contain-paint-formatting-context-margin-001.html contain-paint-formatting-context-margin-001-ref.html
+== contain-paint-ignored-cases-ib-split-001.html contain-paint-ignored-cases-ib-split-001-ref.html
== contain-paint-ignored-cases-internal-table-001a.html contain-paint-ignored-cases-internal-table-001-ref.html
== contain-paint-ignored-cases-internal-table-001b.html contain-paint-ignored-cases-internal-table-001-ref.html
== contain-paint-ignored-cases-no-principal-box-001.html contain-paint-ignored-cases-no-principal-box-001-ref.html
@@ -36,6 +37,7 @@ fuzzy-if(webrender&&winWidget,0-3,0-2) == contain-size-inline-flex-001.html cont
== contain-layout-formatting-context-margin-001.html contain-layout-formatting-context-margin-001-ref.html
== contain-layout-containing-block-fixed-001.html contain-paint-containing-block-fixed-001-ref.html
== contain-layout-containing-block-absolute-001.html contain-paint-containing-block-absolute-001-ref.html
+== contain-layout-ignored-cases-ib-split-001.html contain-layout-ignored-cases-ib-split-001-ref.html
== contain-layout-ignored-cases-no-principal-box-001.html contain-paint-ignored-cases-no-principal-box-001-ref.html
== contain-layout-ignored-cases-no-principal-box-002.html contain-layout-ignored-cases-no-principal-box-002-ref.html
== contain-layout-ignored-cases-no-principal-box-003.html contain-layout-ignored-cases-no-principal-box-003-ref.html
diff --git a/testing/web-platform/meta/css/css-contain/contain-layout-018.html.ini b/testing/web-platform/meta/css/css-contain/contain-layout-018.html.ini
deleted file mode 100644
index b83078d5cc3a..000000000000
--- a/testing/web-platform/meta/css/css-contain/contain-layout-018.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[contain-layout-018.html]
- expected: FAIL
diff --git a/testing/web-platform/meta/css/css-contain/contain-paint-025.html.ini b/testing/web-platform/meta/css/css-contain/contain-paint-025.html.ini
deleted file mode 100644
index ec1c05d716e6..000000000000
--- a/testing/web-platform/meta/css/css-contain/contain-paint-025.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[contain-paint-025.html]
- expected: FAIL