Casetracker module + Calendar module

Hi, I wanted to combine casetracker module and calendar module. Casetracker module simply create a content type which named 'case'. I added this content type to date field named 'duration' and machine name 'field_duration'. I selected 'collect end date' and make it 'requied'.

After I added view from template, I can see my 'field_duration' field and select it. But when I open the view there is no calendar even I added some case with date. (see screenshot)

What do you suggest?