$params['url'] is empty so I don't get proper links for week view from monthly calendar

My monthly calendar displays the week numbers in the left hand column, but the links from there are like

http://2008/W45

In looking at the code, I see that calendar.theme has

line 45: $view->page_url = calendar_page_url($view);

but that $params['url'] is not set before calling calendar_build_calendar at line 73. By inserting

$params['url'] = $view->page_url; at line 64

Things seem to work properly.

I don't know whether this is the proper fix, or whether the calendar.inc or calendar_api.inc calendar_build_* functions should use $views->page_url directly instead of $params['url']