 package org.apache.flex.utils
 {
 	import org.apache.flex.core.IPopUpHost;
-	import org.apache.flex.core.UIBase;
+    import org.apache.flex.core.IChild;
+	import org.apache.flex.core.IUIBase;
 
 	/**
 	 *  The UIUtils class is a collection of static functions that provide utility

		 *  @playerversion AIR 2.6
		 *  @productversion FlexJS 0.0
		 */
		public static function removePopUp(popUp:UIBase):void
		{
			var host:IPopUpHost = popUp.parent as IPopUpHost;
			host.removeElement(popUp);

		 *  @playerversion AIR 2.6
		 *  @productversion FlexJS 0.0
		 */
		public static function center( item:IUIBase, relativeTo:IUIBase ):void
		{
			var xpos:Number = (relativeTo.width - item.width)/2;
			var ypos:Number = (relativeTo.height - item.height)/2;
