[otrs] Clicking on star icon does not remove the star

I am having an issue with the toolbar in the agent interface (the icon with a star that shows unread items). - When I receive a ticket update, the icon toolbar at the top of the OTRS window shows an icon with a star. - Clicking the icon shows the list of updated tickets (in this case, only one). - The icon remains there, until I click it again, even if there are no unread tickets. Hence I need to click the 'star' icon twice to get rid of the notification. Are others seeing this as well? Regards Sander