Currently if the resolution field is populated, the ticket # will show up with strikethrough text. There are workflow work arounds to remove this currently but they do not always apply to every customer that wants to have this option.

If customers could easily change the font variation used when a ticket shows as resolved, it would certainly improve workflow for some customers.

Workaround

If you don't want it, make sure you don't set the resolution field at all. Check your work flow post functions and remove if there are any.