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
schemaCombo.removeAll( );
		}
		try
		{
			if ( jdbcConnection != null )
			{
				isSchemaSupported = metaDataProvider.isSchemaSupported( );
			}
		}
		catch ( Exception e )
		{
			ExceptionHandler.showException( this.getShell( ),
					JdbcPlugin.getResourceString( "exceptionHandler.title.error" ),
					e.getLocalizedMessage( ),
					e );
		}
	}
	/**
	 * Called to indicate that the process of getting the available Db objects
	 * is in progress
	 * 
	 */
	private void setRefreshInfo( )
	{
		if ( rootNode == null )
		{
			return;
		}
		TreeItem item = new TreeItem( rootNode, 0 );
		item.setText( JdbcPlugin.getResourceString( "tablepage.refreshing" ) );