*** DO NOT LAND *** Attempt to understand Regions complexity

Source/core/rendering/RenderLayerStackingNode.cpp

Index: Source/core/rendering/RenderLayerStackingNode.cpp
diff --git a/Source/core/rendering/RenderLayerStackingNode.cpp b/Source/core/rendering/RenderLayerStackingNode.cpp
index eef589fe5097607e5314fc64a4f6c5b1a8a419dc..0ff68635399c45c398c6d0666b3fe549bf6cc250 100644
--- a/Source/core/rendering/RenderLayerStackingNode.cpp
+++ b/Source/core/rendering/RenderLayerStackingNode.cpp
@@ -303,7 +303,7 @@ void RenderLayerStackingNode::collectLayers(OwnPtr<Vector<RenderLayerStackingNod
     }
 
     // Overflow layers are just painted by their enclosing layers, so they don't get put in zorder lists.
-    if (!isNormalFlow && !layer()->isOutOfFlowRenderFlowThread()) {
+    if (!isNormalFlow) {
         // Determine which buffer the child should be in.
         OwnPtr<Vector<RenderLayerStackingNode*> >& buffer = (zIndex() >= 0) ? posBuffer : negBuffer;
 
@@ -426,8 +426,7 @@ bool RenderLayerStackingNode::shouldBeNormalFlowOnlyIgnoringCompositedScrolling(
         || renderer()->hasClipPath()
         || renderer()->hasFilter()
         || renderer()->hasBlendMode()
-        || layer()->isTransparent()
-        || renderer()->style()->hasFlowFrom();
+        || layer()->isTransparent();
 
     return couldBeNormalFlow && !preventsElementFromBeingNormalFlow;
 }