--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -1225,16 +1225,19 @@ nsIFrame::IsSVGTransformed(gfx::Matrix *
                            gfx::Matrix *aFromParentTransforms) const
 {
   return false;
 }
 
 bool
 nsIFrame::Extend3DContext() const
 {
+  if (!(mState & NS_FRAME_MAY_BE_TRANSFORMED)) {
+    return false;
+  }
   const nsStyleDisplay* disp = StyleDisplay();
   if (disp->mTransformStyle != NS_STYLE_TRANSFORM_STYLE_PRESERVE_3D ||
       !IsFrameOfType(nsIFrame::eSupportsCSSTransforms)) {
     return false;
   }
 
   // If we're all scroll frame, then all descendants will be clipped, so we can't preserve 3d.
   if (GetType() == nsGkAtoms::scrollFrame) {