[Evolution] "Open Web Page" on task does nothing

[Adam Tauno Williams <awilliam whitemice org>]

I have a CalDAV to-do list.  The tasks all have a URL property that
appears in Open Task -> Details: "Web Page".  And I can click on the
'go' button next to that field in the dialog and go to the web page.
But right-clicking on a task in the task list view and selecting "Open
Web Page" does nothing as far as I can tell.  Any tips?  The other
mechanism [using the dialog] is rather more cumbersome.