void WindowOnActivated(object sender, WindowActivatedEventArgs windowActivatedEventArgs)
{
// If the TimePicker is in a TableView or ListView, when the application loses focus
// the TextBlock/ComboBox controls (UWP and 8.1, respectively) which display its selected value
// will go blank.
// To fix this, we have to signal the renderer to invalidate if
// Window.Activated occurs.
ForceInvalidate?.Invoke(this, EventArgs.Empty);
}
void PickerOnDropDownClosed(object sender, object o)
{
// If the TimePicker is in a TableView or ListView and the user
// opens one of the dropdowns but does not actually change the value,
// when the dropdown closes, the selected value will go blank
// To fix this, we have to invalidate the control
// This only applies to Windows 8.1
ForceInvalidate?.Invoke(this, EventArgs.Empty);
}