Bug 882384 - Make sure the status panel always get its own layer. r=roc

browser/base/content/tabbrowser.xml

@@ -186,6 +186,7 @@
           if (!this._statusPanel) {
             this._statusPanel = document.createElementNS(this.namespaceURI, "statuspanel");
             this._statusPanel.setAttribute("inactive", "true");
+            this._statusPanel.setAttribute("layer", "true");
             this._appendStatusPanel();
           }
           return this._statusPanel;

layout/generic/nsFrame.cpp

@@ -2017,6 +2017,8 @@ nsIFrame::BuildDisplayListForStackingContext(nsDisplayListBuilder* aBuilder,
         new (aBuilder) nsDisplayBlendContainer(aBuilder, this, &resultList));
   }
 
+  CreateOwnLayerIfNeeded(aBuilder, &resultList);
+
   aList->AppendToTop(&resultList);
 }
 
@@ -8054,7 +8056,9 @@ void
 nsIFrame::CreateOwnLayerIfNeeded(nsDisplayListBuilder* aBuilder, 
                                  nsDisplayList* aList)
 {
-  if (GetContent()->HasAttr(kNameSpaceID_None, nsGkAtoms::layer)) {
+  if (GetContent() &&
+      GetContent()->IsXUL() &&
+      GetContent()->HasAttr(kNameSpaceID_None, nsGkAtoms::layer)) {
     aList->AppendNewToTop(new (aBuilder) 
         nsDisplayOwnLayer(aBuilder, this, aList));
   }