DateTime picker visual bug

Hello, I have dialog and date time picker inside. Dialog has scroll bar if I scroll to the bottom of it and try to open date time picked some of it is hidden

Any pointer of what could be wrong? Browser dimensions: 900x666

If you need any more details please let me know

The browser windows is too small and clips the bottom end of the datepicker.

@korchev I understand that... Question is why it's showing it below and not above if it does not fit?

Because it seems there isn't enough space above as well. This is how it behaves.