Bug 207564 Column sorting based on data type
Only string sorting happens when a column is selected in preview result page of DataSet Editor irrespective of type of data shown in that column. I'd like to be able to sort the data based on its datatype when a column is selected.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/data/ui/util/DataSetProvider.java
return session.getModelAdaptor( ).adaptDataSource( dataSource );
	}
	
	/**
	 * Get cached data set item model. If none is cached, return null;
	 * 
	 * @param ds
	 * @param columns
	 */
	public DataSetViewData[] getCachedDataSetItemModel( DataSetHandle ds )
	{
		DataSetViewData[] result = (DataSetViewData[]) this.htColumns.get( ds );
		if ( result == null )
		{
			DataRequestSession session;
			try
			{
				DataSessionContext context = new DataSessionContext( DataSessionContext.MODE_DIRECT_PRESENTATION,
						ds.getModuleHandle( ) );
				session = DataRequestSession.newSession( context );
				result = this.populateAllOutputColumns( ds, session );
				return result;
			}
			catch ( BirtException e )
			{
				result = new DataSetViewData[0];
			}
		}
		return result;
	}