1 files changed, 9 insertions, 0 deletions
diff --git a/components/layout_2020/style_ext.rs b/components/layout_2020/style_ext.rs
index 44245e2c89d..7ed41d1cd91 100644
--- a/components/layout_2020/style_ext.rs
+++ b/components/layout_2020/style_ext.rs
@@ -56,6 +56,7 @@ pub(crate) trait ComputedValuesExt {
     fn has_transform_or_perspective(&self) -> bool;
     fn effective_z_index(&self) -> i32;
     fn establishes_stacking_context(&self) -> bool;
+    fn establishes_containing_block(&self) -> bool;
     fn establishes_containing_block_for_all_descendants(&self) -> bool;
 }
 
@@ -233,6 +234,14 @@ impl ComputedValuesExt for ComputedValues {
         !self.get_position().z_index.is_auto()
     }
 
+    fn establishes_containing_block(&self) -> bool {
+        if self.establishes_containing_block_for_all_descendants() {
+            return true;
+        }
+
+        self.clone_position() != ComputedPosition::Static
+    }
+
     /// Returns true if this style establishes a containing block for all descendants
     /// including fixed and absolutely positioned ones.
     fn establishes_containing_block_for_all_descendants(&self) -> bool {