[Lazarus] Howto dropdown the calendar of TDateEdit programmatically

[John Landmesser]

Hi,

i want to dropdown the calendar of an DateEdit at start of my app, so 
the user will see what to do next.

There is a "DateEdit.Button.Clicḱ" procedure and 
"TCustomMaskEdit.DoButtonClick", but they don't show the calendar.

Is it possible to show the calendar by code?

thank you for a tipp!!