Final answer:
To prevent the Datepicker component from opening automatically on a VF page, remove the autofocus attribute from the Datepicker or set it to another element, or use JavaScript to change the focus or blur the Datepicker after the page load.
Step-by-step explanation:
To avoid the Datepicker component opening automatically when it is the first component on a Visualforce (VF) page, you need to modify the component's or containing element's autofocus attribute. By default, if the Datepicker is the first input element in the form, the browser might automatically focus on it on page load, causing it to open. To prevent this, ensure that either the Datepicker does not have the autofocus attribute or set the attribute to another element that intentionally should have the focus when the page loads.
Alternatively, you can use JavaScript to set the focus to another element or to blur the Datepicker after the page has finished loading. This approach allows you to control the user experience more directly and prevent unwanted opening of the Datepicker component.