     //  requestedColumnCount
     //----------------------------------
 
-    [Inspectable(category="General")]
+    [Inspectable(category="General", minValue="-1")]
 
     /**
      *  @copy spark.layouts.TileLayout#requestedColumnCount

    //  horizontalAlign
    //----------------------------------
    
    [Inspectable(category="General", enumeration="left,center,right,justify,contentJustify", defaultValue="left")]

    /**
     *  @copy spark.layouts.TileLayout#horizontalAlign

    //----------------------------------
    
    [Bindable("propertyChange")]
    [Inspectable(category="General", minValue="0.0")]

    /**
     *  @copy spark.layouts.TileLayout#rowHeight
