Modal and overlay behavior – When to close the modal

Considering a modal/popup over an overlay, I know that there are certain acceptable ways (as per need), as to which interaction should close the modal, as below:

  1. Clicking on overlay
  2. Hitting esc key
  3. Click on the modal/popup (dont release) and drag the mouse outside the modal/popup and till overlay, then release
  4. Having a close button or icon on modal to do so

Apart from this, is it a good idea to close the modal, if a user clicks on overlay (but not release), starts dragging from the overlay and goes inside the modal window (opposite of 3) and then release the mouse.

The modal in question here basically contains a long form where user has to enter/edit details to save. The form already has a cancel, save button.