title: Programmatically open PrimeNG calendar in modal popup
body: <p>How to make PrimeNG calendar at open state by default in modal popup ? Or how to trigger click event to open PrimeNG calendar which is in modal popup by typescript ? </p>
  
  <p>If I used in HTML itself, it triggers the click event to open calendar by <code>showoverlay()</code>, but when using in modal popup, since popup is not in DOM element, it shows error as <code>showoverlay()</code> is not a function.</p>