User Picker does not pick the person you select

When editing a notification scheme it is possible to let a single JIRA-user know when changes happen. This is done by selecting an action in the notification scheme and then selecting the "Single User" radio button.

If I just manually write the username in the Single User text field there is no problem, but if I click on the User Picker and click on a user here, the User Picker window closes correctly, but no user is displayed in the text field.

There is no output in the catalina.out either.

/watson