Bug 199021 Error message pops up several times when click an invalid dataset
Description: There is a sqlserver datasource and dataset, remove the jtds driver to let the dataset invalid. Double click on the dataset, the error message will pop up serveral times. Build version:2.2.0.v20070807-0630 Steps to reproduce: 1. Create a sqlserver datasource and dataset. 2. Remove the jtds driver, and the dataset will be invalid. 3. Double click on the dataset. Expect result: Error message pops up once to indicate the problem. Actual result: Error message pops up serveral times.
data/org.eclipse.birt.report.data.oda.jdbc.ui/src/org/eclipse/birt/report/data/oda/jdbc/ui/editors/SQLDataSetEditorPage.java
* @param pageName
	 */
	public SQLDataSetEditorPage( String pageName )
	{
		super( pageName );
	}
	/*
	 * @see org.eclipse.datatools.connectivity.oda.design.ui.wizards.DataSetWizardPage#createPageCustomControl(org.eclipse.swt.widgets.Composite)
	 */
	public void createPageCustomControl( Composite parent )
	{
		setControl( createPageControl( parent ) );
		initializeControl( );
		Utility.setSystemHelp( getControl( ),
				IHelpConstants.CONEXT_ID_DATASET_JDBC );
	}
	/**
	 * create page control for sql edit page
	 * 
	 * @param parent
	 * @return
	 */
	private Control createPageControl( Composite parent )
	{
		SashForm SashForm = new SashForm( parent, SWT.HORIZONTAL );
		SashForm.setLayoutData( new GridData( GridData.FILL_BOTH ) );
		initialImage( );
		initialJdbcInfo( );
		createTableSelectionComposite( SashForm );
		createTextualQueryComposite( SashForm );