title: Adding button in Actionscript code : Using Flex Builder
body: <p>I created a new actionscript project using Flex Builder 3 and tried</p>
  
  <p>to run the following file. I get this error : </p>
  
  <p>Definitions: fl.controls:Button could not be found.
  All I want to do is, to add a button to the application.
  How could I do it?</p>
  
  <pre><code>package  {
          import PaperBase;
          import org.papervision3d.objects.primitives.Cone;
          import fl.controls.Button;
          import fl.controls.Label;
          import fl.events.ComponentEvent;
  
          public class cone1 extends PaperBase {
              public var cone:Cone = new Cone();
              protected var sceneWidth:Number;
              protected var sceneHeight:Number;
              public function cone1() {
                  sceneWidth = stage.stageWidth
                  sceneHeight = stage.stageHeight;
                  init(sceneWidth*0.5,sceneHeight*0.5);//position of the cone
              }
              override protected function init3d():void {
                  cone.scale = 5;
                  cone.pitch(-40)
                  default_scene.addChild(cone);
              }
              override protected function processFrame():void {
                  cone.yaw(1);//rotation speed
              }
          }
      }
  </code></pre>