.NET Compact Framework Form not closing properly

Question

I have a form in a Compact Framework application. When the user presses the 'X' or 'OK' button in the top right, the screen doesn't refresh until the users taps anywhere on the screen.

The form is being shown using this code:

using (var customerDetailsForm = ObjectFactory.Get<CustomerDetailsForm>())
{
    customerDetailsForm.AssignCustomerId(customerId);
    customerDetailsForm.ShowDialog();
}