diff --git a/layout/base/FrameLayerBuilder.cpp b/layout/base/FrameLayerBuilder.cpp
index 148d04ee02c..bd622a54dad 100644
--- a/layout/base/FrameLayerBuilder.cpp
+++ b/layout/base/FrameLayerBuilder.cpp
@@ -1666,6 +1666,11 @@ ContainerState::FindFixedPosFrameForLayerData(const nsIFrame* aAnimatedGeometryR
                                               nsIntRegion* aVisibleRegion,
                                               bool* aIsSolidColorInVisibleRegion)
 {
+  if (!mManager->IsWidgetLayerManager()) {
+    // Never attach any fixed-pos metadata to inactive layers, it's pointless!
+    return nullptr;
+  }
+
   nsPresContext* presContext = mContainerFrame->PresContext();
   nsIFrame* viewport = presContext->PresShell()->GetRootFrame();
   const nsIFrame* result = nullptr;