File to Case link does not work on Find Activities selector

Clicking File to Case on an activity row from Find Activities selector does not load the expected jquery dialog form, but instead goes to another page with an empty form. This action link does work properly when the Activity Selector is embedded in contact/view/activity tab.

Not sure if it's related but the call to include ActivityToCase.tpl from Selector/Activity.tpl includes a $contactId variable - which would not make sense in the Find Activities flow (since we're not looking at a specific contact record on that page):

{include file="CRM/Case/Form/ActivityToCase.tpl" contactID=$contactId}