Bug 130068 [Regression]Report Parameter window doesn't pop up when preview a report with parameter.
Description: Report Parameter window doesn't pop up when preview a report with parameter. Steps to reproduce: 1. New a report parameter without default value. 2. Drag it to Layout. 3. Click Preview in Layout. Expected result: Window pops up for value input. Actual result: Some required parameter values are not set or set to incompatible data type.
UI/org.eclipse.birt.report.designer.ui.preview/src/org/eclipse/birt/report/designer/ui/preview/editors/ReportPreviewFormPage.java
return true;
	}
	/* (non-Javadoc)
	 * @see org.eclipse.ui.forms.editor.IFormPage#getPartControl()
	 */
	public Control getPartControl( )
	{
		return control;
	}
	/* (non-Javadoc)
	 * @see org.eclipse.ui.forms.editor.IFormPage#getId()
	 */
	public String getId( )
	{
		return ID;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.IWorkbenchPart#createPartControl(org.eclipse.swt.widgets.Composite)
	 */
	public void createPartControl( Composite parent )
	{
		super.createPartControl( parent );
		Control[] children = parent.getChildren( );
		control = children[children.length - 1];
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.birt.report.designer.ui.editors.IReportEditorPage#markPageStale(int)