Bug 147977 Chart editor does not use container's column bindings
1) create data source 2) create data set: select * from customers 3) create table 4) bind country, customer name to table 5) group by country 6) create a binding for total_by_country which aggregates # of customers in each country. put a data element in group footer and bind to total_by_country 7) in group header put chart 8) in data tab specify inherit from container Result: You see columns for report data set created in step 2. Expected Result: Just 3 columns for the 3 bindings created in 4 and 6.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/PreparedQuery.java
* @param afterGroup
	 * @param cx
	 * @throws DataException 
	 */
	private void prepareExpressions( Collection expressions, int groupLevel,
			boolean afterGroup, boolean isDetailedRow, Context cx ) throws DataException
	{
	    if ( expressions == null )
	        return;
	    
	    AggregateRegistry reg = this.aggrTable.getAggrRegistry( groupLevel,
	    		-1,
				isDetailedRow,
				cx );
	    Iterator it = expressions.iterator();
	    while ( it.hasNext() )
	    {
	        prepareExpression((IBaseExpression) it.next(), groupLevel, cx, reg);
	    }
	}
	
	/**
	 * Prepares one expression
	 * 
	 * @param expr
	 * @param groupLevel
	 * @param cx
	 * @param reg
	 */
	private void prepareExpression( IBaseExpression expr, int groupLevel,