Edit 2: Thank you all for your feedback. I solved the problem by adding this to my SelectedDatesChanged event:
Mouse.Capture(null);
When I select a
I had the same issue weeks ago, you can use DatePicker which is a control that contains a Calendar, the calendar is displayed once the user clicks a button and when you select a date its automatically closed, the DatePicker Contains also a textbox when the date is visible, you can make it ReadOnly if you want: here a sample code for using DatePicker:
Hope this helps.
result :