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 item
	 */
	private void selectNode( TreeItem item )
	{
		TreeItem[] selectedItem = new TreeItem[1];
		selectedItem[0] = item;
		availableDbObjectsTree.setSelection( selectedItem );
		availableDbObjectsTree.setFocus( );
	}
	/**
	 * @param schemaRs:
	 *            The ResultSet containing the List of schema
	 * @return A List of schema names
	 */
	private ArrayList getAllSchemaList( ResultSet schemaRs )
	{
		if ( schemaRs == null )
		{
			return null;
		}
		ArrayList allSchemas = new ArrayList( );
		try
		{
			while ( schemaRs.next( ) )
			{
				allSchemas.add( schemaRs.getString( "TABLE_SCHEM" ) );
			}