Comment 4 for bug 1775940

Pushed all the way to rel_3_3. Thanks, Jason and John!

I note that if a user types in the date input, the Javascript console will log a bunch of errors of the form "TypeError: $scope.dates.start_date is undefined". This is noisy, but I'm letting that go for now since at first glance it looks like a fix for that would be a little tricky if we want to avoid refreshing the grid while one of the date inputs is in an invalid state.