1 files changed, 4 insertions, 3 deletions
diff --git a/layout/xul/nsRootBoxFrame.cpp b/layout/xul/nsRootBoxFrame.cpp
index 26e94faea..fe41dce52 100644
--- a/layout/xul/nsRootBoxFrame.cpp
+++ b/layout/xul/nsRootBoxFrame.cpp
@@ -75,6 +75,7 @@ public:
                                nsEventStatus* aEventStatus) override;
 
   virtual void BuildDisplayList(nsDisplayListBuilder*   aBuilder,
+                                const nsRect&           aDirtyRect,
                                 const nsDisplayListSet& aLists) override;
 
   /**
@@ -175,14 +176,14 @@ nsRootBoxFrame::Reflow(nsPresContext*           aPresContext,
 
 void
 nsRootBoxFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
+                                 const nsRect&           aDirtyRect,
                                  const nsDisplayListSet& aLists)
 {
   if (mContent && mContent->GetProperty(nsGkAtoms::DisplayPortMargins)) {
     // The XUL document's root element may have displayport margins set in
     // ChromeProcessController::InitializeRoot, and we should to supply the
     // base rect.
-    nsRect displayPortBase = 
-      aBuilder->GetVisibleRect().Intersect(nsRect(nsPoint(0, 0), GetSize()));
+    nsRect displayPortBase = aDirtyRect.Intersect(nsRect(nsPoint(0, 0), GetSize()));
     nsLayoutUtils::SetDisplayPortBase(mContent, displayPortBase);
   }
 
@@ -191,7 +192,7 @@ nsRootBoxFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
   // of a background display list element.
   DisplayBorderBackgroundOutline(aBuilder, aLists, true);
 
-  BuildDisplayListForChildren(aBuilder, aLists);
+  BuildDisplayListForChildren(aBuilder, aDirtyRect, aLists);
 }
 
 nsresult