diff --git a/layout/base/nsCSSRendering.cpp b/layout/base/nsCSSRendering.cpp
index 55c364bcd054..c9b2b13bd239 100644
--- a/layout/base/nsCSSRendering.cpp
+++ b/layout/base/nsCSSRendering.cpp
@@ -1382,8 +1382,9 @@ nsCSSRendering::PaintBoxShadowOuter(nsPresContext* aPresContext,
shadowContext->SetMatrix(
shadowContext->CurrentMatrix().Translate(devPixelOffset));
- nsRect nativeRect;
- nativeRect.IntersectRect(frameRect, aDirtyRect);
+ nsRect nativeRect = aDirtyRect;
+ nativeRect.MoveBy(-nsPoint(shadowItem->mXOffset, shadowItem->mYOffset));
+ nativeRect.IntersectRect(frameRect, nativeRect);
nsRenderingContext wrapperCtx(shadowContext);
aPresContext->GetTheme()->DrawWidgetBackground(&wrapperCtx, aForFrame,
styleDisplay->mAppearance, aFrameArea, nativeRect);
diff --git a/layout/reftests/box-shadow/1212823-1-ref.html b/layout/reftests/box-shadow/1212823-1-ref.html
new file mode 100644
index 000000000000..91cf26d3ccce
--- /dev/null
+++ b/layout/reftests/box-shadow/1212823-1-ref.html
@@ -0,0 +1,7 @@
+
+
+
+
+
+
+
diff --git a/layout/reftests/box-shadow/1212823-1.html b/layout/reftests/box-shadow/1212823-1.html
new file mode 100644
index 000000000000..2337ddf75f1b
--- /dev/null
+++ b/layout/reftests/box-shadow/1212823-1.html
@@ -0,0 +1,6 @@
+
+
+
+
+
+
diff --git a/layout/reftests/box-shadow/reftest.list b/layout/reftests/box-shadow/reftest.list
index e6dabf777566..a5a57d1c32aa 100644
--- a/layout/reftests/box-shadow/reftest.list
+++ b/layout/reftests/box-shadow/reftest.list
@@ -36,3 +36,4 @@ fuzzy-if(winWidget,5,30) == fieldset.html fieldset-ref.html # minor anti-aliasin
fuzzy-if(winWidget,5,30) == fieldset-inset.html fieldset-inset-ref.html # minor anti-aliasing problem on Windows
== 1178575.html 1178575-ref.html
== 1178575-2.html 1178575-2-ref.html
+fuzzy(159,2) fails-if(!d2d) == 1212823-1.html 1212823-1-ref.html