diff --git a/suite/modules/WindowsPreviewPerTab.jsm b/suite/modules/WindowsPreviewPerTab.jsm
index e5cee7627c..1100da8ec6 100644
--- a/suite/modules/WindowsPreviewPerTab.jsm
+++ b/suite/modules/WindowsPreviewPerTab.jsm
@@ -325,14 +325,6 @@ PreviewController.prototype = {
   }
 };
 
-XPCOMUtils.defineLazyGetter(PreviewController.prototype, "canvasPreviewFlags",
-  function () { let canvasInterface = Ci.nsIDOMCanvasRenderingContext2D;
-                return canvasInterface.DRAWWINDOW_DRAW_VIEW
-                     | canvasInterface.DRAWWINDOW_DRAW_CARET
-                     | canvasInterface.DRAWWINDOW_ASYNC_DECODE_IMAGES
-                     | canvasInterface.DRAWWINDOW_DO_NOT_FLUSH;
-});
-
 ////////////////////////////////////////////////////////////////////////////////
 //// TabWindow