Focus issue with Calendar in Dialog

[corvinsz]

Bug explanation

After having selected a day in a Calendar in a dialog, users have to click twice to close the dialog.
It seems like the first click only restores focus to the dialog (or window)?

Here is an example where I have to click the "OK" button twice to for the dialog to close:

CalendarInDialog.mp4

Version

5.3.0

[corvinsz]

After some research I was surprised to see that this is a WPF "issue".
From my understanding it's by design and not considered a bug, which I find very odd.
source 1, source 2, source 3

@Keboo
The following is a workaround for this issue.
Thoughts on adding an AP (e.g. CalendarAssist:SingleClickDefocus="True")? Or should consumers be responsible of handling this problem themself?

private void Calendar_GotMouseCapture(object sender, MouseEventArgs e)
{
    UIElement originalElement = e.OriginalSource as UIElement;
    if (originalElement is CalendarDayButton || originalElement is CalendarItem)
    {
        originalElement.ReleaseMouseCapture();
    }
}