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
}
			public void dispose( )
			{
			}
			public void inputChanged( Viewer viewer, Object oldInput,
					Object newInput )
			{
			}
		} );
		filterComboViewer.setLabelProvider( new LabelProvider( ) {
			public String getText( Object inputElement )
			{
				DbType dbType = (DbType) inputElement;
				return dbType.getName( );
			}
		} );
		filterComboViewer.setInput( dbTypeList );
		
		filterComboViewer.getCombo( ).select( 0 );
	}
	/**
	 * This method is invoked when the find button is clicked It populates the
	 * Available Data Base obecets ( in the Tree control )
	 */
	protected void populateAvailableDbObjects( )
	{
		DataSetDesign dataSetDesign = getDataSetDesign( );
		DataSourceDesign curDataSourceDesign = dataSetDesign.getDataSourceDesign( );
		if ( curDataSourceDesign == prevDataSourceDesign )
		{