Bug 153387 Database item can't be dragged and dropped onto editor field
Steps to reproduce: 1.Start up BIRT in Mac OS X; 2.File->New->Project; 3.File->New->Report Design; 4.In Data Explorer, create a New Data Source, and choose "Classic Models Inc. Sample DataBase", press "Next" and then press "finish"; 5.In Data Explorer, create a New Data Set, press "Next"; 6.In the popup window, expand the "CLASSICMODELS", select and drag a item onto the editor field at right side.
data/org.eclipse.birt.report.data.oda.jdbc.ui/src/org/eclipse/birt/report/data/oda/jdbc/ui/editors/SQLDataSetEditorPage.java
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 )
		{
			if ( ( cachedSearchTxt == searchTxt.getText( ) || ( cachedSearchTxt != null && cachedSearchTxt.equals( searchTxt.getText( ) ) ) )
					&& ( cachedDbType == getSelectedDbType( ) || ( cachedDbType != null && cachedDbType.equals( getSelectedDbType( ) ) ) ) )
			{
				if ( schemaList != null && schemaList.size( ) > 0 )
				{
					if ( cachedSchemaComboIndex == schemaCombo.getSelectionIndex( ) )
					{
						return;