Bug 122941 Group interval range resets to 1
1. Create a group based on orders.orderNumber. 2. Specify an interval range of 100. 3. Do not check "Use fixed base value for interval" 4. Preview the report. Report groups on every order number. 5. Open the group editor. The interval range is set to 1.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/GroupDialog.java
intervalRange = new Spinner( intervalArea, SWT.NONE );
		intervalRange.setLayoutData( new GridData( GridData.HORIZONTAL_ALIGN_FILL ) );
		intervalRange.setMinimum( 0 );
		intervalRange.setMaximum( Integer.MAX_VALUE );
		intervalRange.setStep( 1 );
		
		intervalBaseButton = new Button( composite, SWT.CHECK );
		intervalBaseButton.setText( GROUP_DLG_INTERVAL_BASE_LABEL ); 
		intervalBaseButton.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		intervalBaseButton.addSelectionListener( new SelectionAdapter( ) {
			public void widgetSelected( SelectionEvent e )
			{
				intervalBaseText.setEnabled( intervalBaseButton.getSelection( ) );
			}
		} );
		intervalBaseText = new Text( composite, SWT.SINGLE | SWT.BORDER );
		intervalBaseText.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
	}
	/**
	 * Creates the group area
	 * 
	 * @param parent
	 *            the parent composite
	 */
	private void createGroupArea( Composite parent )
	{
		Composite composite = new Composite( parent, SWT.NONE );
		composite.setLayoutData( new GridData( GridData.FILL_HORIZONTAL
				| GridData.VERTICAL_ALIGN_BEGINNING ) );
		composite.setLayout( new GridLayout( ) );