     
     private var _columnWidth:Number;
 
-    [Inspectable(category="General")]
+    [Inspectable(category="General", minValue="0.0")]
 
     /**
      *  If the <code>variableColumnWidth</code> property is <code>false</code>, 


    private var _paddingLeft:Number = 0;
    
    [Inspectable(category="General")]

    /**
     *  Number of pixels between the container's left edge


    private var _paddingTop:Number = 0;
    
    [Inspectable(category="General", minValue="0.0")]

    /**
     *  The minimum number of pixels between the container's top edge and
