Bug 141959 Changing data set didn't clean old column bindings
Steps to reproduce: 1.Add two data sets, "ds1" and "ds2" 2.Add a table, binding with "ds1". All "ds1" column bindings generate automatically, that's good 3.Change "ds1" to None Expected result: All "ds1" column bindings should be cleaned Actual result: All "ds1" column bindings are still there. If changing to "ds2", "ds2" column bindings will be added after them.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ColumnBindingDialog.java
public void removeListener( ILabelProviderListener listener )
		{
		}
	};
	private String highLightName = null;
	private ICellModifier cellModifier = new ICellModifier( ) {
		public boolean canModify( Object element, String property )
		{
			if ( property == null
					|| ( element == dummyChoice && !COLUMN_NAME.equals( property ) ) )
			{
				return false;
			}
			return true;
		}
		public Object getValue( Object element, String property )
		{
			if ( element == dummyChoice )
			{
				ComputedColumn column = StructureFactory.newComputedColumn( inputElement,
						DEFAULT_COLUMN_NAME );
				column.setExpression( "" ); 
				if ( DEUtil.getGroupControlType( inputElement )
						.equals( DEUtil.TYPE_GROUP_GROUP ) )
				{
					column.setAggregrateOn( ( (GroupHandle) DEUtil.getGroups( inputElement )
							.get( 0 ) ).getName( ) );
				}
				addBinding( column );
				highLightName = column.getName( );