Not possible to mark response as read for deleted question

Hi,

Someone responded to a comment I made here but before I managed to click on it the question was deleted. I am able to read the response by clicking on the red envelope icon in the top bar, but the problem is the red envelope does not go away.

When I click on the response, I get the message Sorry, this content is no longer available and the response remains marked as unread.

This appears to be a bug in the software running this web forum. How can we fix this, and is there a workaround to mark a response as read?

Please mark the response (using checkbox at the left of it at the Notifications page of your profile), and use Mark seen link at the top of the Responses list.

Thanks, that sorted it out. (The response was far down the list and the Mark seen is in tiny font at the top, so it was not easy for me to spot)