ExtJS 3.x: How to disable the red mark indicating a dirty record in ExtJS EditorGridPanel

EditorGridPanel shows a small red triangular corner on the column that is edited to indica开发者_StackOverflowte an unsaved record.

Since I am using autoSave, I don't need to indicate the record as dirty/unsaved.

Is there an easy way to disable this ?

view: Ext.grid.GridView({markDirty: false})

or

viewConfig: {
    markDirty: false
}

.x-grid3-dirty-cell {
  background-image: none;
}