Bug 183308 IllegalArgumentException occurs after insert a empty group on a List report item[0001]
Description: IllegalArgumentException occurs after insert a empty group on a List report item[0001] Build number: 2.2.0.v20070419-0945 Steps to reproduce: 1, Insert a list 2, Insert a group on the list, only specify the Group On: "aa" Expected result: No exception Actual result: IllegalArgumentException occurs Error log: java.lang.IllegalArgumentException: Argument cannot be null at org.eclipse.swt.SWT.error(SWT.java:3483) at org.eclipse.swt.SWT.error(SWT.java:3422) at org.eclipse.swt.SWT.error(SWT.java:3393) at org.eclipse.swt.widgets.Widget.error(Widget.java:432) at org.eclipse.swt.widgets.Text.setText(Text.java:1793) at org.eclipse.birt.report.designer.ui.dialogs.GroupDialog$6.focusLost(GroupDialog.java:485) at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:136) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:938) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:962)
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/GroupDialog.java
private Class getColumnType( )
	{
		for ( int i = 0; i < columnList.size( ); i++ )
		{
			Object dataSetItemModel = columnList.get( i );
			if ( dataSetItemModel instanceof DataSetItemModel )
			{
				if ( ( (DataSetItemModel) dataSetItemModel ).getDataSetColumnName( )
						.equals( keyChooser.getText( ) ) )
					return DataType.getClass( ( (DataSetItemModel) dataSetItemModel ).getDataType( ) );
			}
		}
		return null;
	}
	/**
	 * Reset intervalType
	 * 
	 * @param choice
	 */
	private void resetIntervalType( IChoice[] choice )
	{
		intervalType.removeAll( );
		for ( int i = 0; i < choice.length; i++ )
		{
			intervalType.add( choice[i].getDisplayName( ) );
		}
		intervalType.setData( choice );
		intervalType.select( 0 );
		intervalType.addSelectionListener( new SelectionAdapter( ) {
			public void widgetSelected( SelectionEvent e )