This is one of those posts I hops save somebody the time I wasted today trying to work this out.

If you have an ActionScript class that extends the TitleWindow (or Panel for that matter) class and you want to add a ControlBar in the over-ridden createChildren function then you need to know to add a call to the createComponentsFromDescriptors() function at the end of it.

See last line of this example:

package
{
        import mx.controls.Button;
        import mx.controls.LinkButton;
        import mx.controls.TextInput;
        
        public class SaveDialog extends TitleWindow
        {
                private static var _dialog:SaveDialog;
                
                public function SaveDialog()
                {
                        super();
                }
                
                override protected function createChildren():void
                {
                        super.createChildren();
                        
                        var _titleField:TextInput = new TextInput();
                        _titleField.text="a field";
                        addChild(_titleField);  
                        
                        var buttons:ControlBar = new ControlBar();
                                                
                        var _saveButton:Button = new Button();
                        _saveButton.label="Save";                       
                        buttons.addChild(_saveButton);
                        
                        _cancelButton = new LinkButton();
                        _cancelButton.label = "Cancel";
                        buttons.addChild(_cancelButton);
                        
                        addChild(buttons);
                        
                        //have to call this at end to put control bar in right place!
                        createComponentsFromDescriptors();
                }
                
        }
}

If you don't call this function the buttons get added, just not where you'd expect them to (at the bottom and outside the Panel's main content area.

Took me hours and hours and searching and messing about today to find that out. Hopefully you found this quicker.