Is there a way to create a widget underneath a button when pressed similar to a combobox?

I’m creating a date selector but I’m having trouble finding a way to have the calendar widget that is created to show up underneath the button similar to a combobox.

When pressing the first date and the second date buttons I would like my calendar widget to show up underneath and overlap the content in the widget. I originally just placed my calendar widget in the correct location in the canvas panel so when it was added to the viewport it would be in the desired place but the second buttons location changes depending on the length of the date chosen in the first button.

Is there a way to make a combobox work where instead of showing a list it instead shows one custom widget and that one widget cannot be selected but still interacted with?

Thank you for any help.

Try to use Menu Anchor:

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