Why need to drupal_set_title ?

'theme_zoomify' calls 'drupal_set_title'. Does it need to?

If I comment it out, it doesn't seem to cause any problems. When I click the 'zoomify' tab of the node, the node's title is still displayed correctly.

With the line in place, I get problems with another page I've built, http://gwulo.com/booth-tram-ride. It embeds a view that is a list of nodes, and some of those nodes display the zoomify viewer (see http://drupal.org/node/371818#comment-2116370). With the line commented out, you see the correct page title 'Views along the tram line in the 1950s'. With the line in place, the page title changes to the title of the last node in the list that showed a zoomify viewer, ie '1950s Causeway Road & Typhoon Shelter'