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
catch ( NumberFormatException e )
				{
					return;
				}
			}
		} );
		
		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 ) );
		hideDetail = new Button( composite, SWT.CHECK );
		hideDetail.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		hideDetail.setText( GROUP_DLG_HIDE_DETAIL );
	}
	/**
	 * Creates the group area
	 * 
	 * @param parent
	 *            the parent composite
	 */
	private void createGroupArea( Composite parent )
	{