Bug 312859 The list of operator for Chart filter does not provide 30 visible items
chart/org.eclipse.birt.chart.reportitem.ui/src/org/eclipse/birt/chart/reportitem/ui/dialogs/ChartCubeFilterConditionBuilder.java
public void widgetDefaultSelected( SelectionEvent e )
			{
			}
			public void widgetSelected( SelectionEvent e )
			{
				String value = addExpressionValue.getText( ).trim( );
				if ( valueList.indexOf( value ) < 0 )
				{
					valueList.add( value );
					tableViewer.refresh( );
					updateButtons( );
					addExpressionValue.setFocus( );
					addExpressionValue.setText( "" ); 
				}
				else
				{
					addBtn.setEnabled( false );
				}
			}
		} );
		new Label( group, SWT.NONE );
		int tableStyle = SWT.SINGLE
				| SWT.BORDER
				| SWT.H_SCROLL
				| SWT.V_SCROLL
				| SWT.FULL_SELECTION;
		table = new Table( group, tableStyle );
		data = new GridData( GridData.FILL_VERTICAL );
		data.horizontalSpan = 4;
		table.setLayoutData( data );