modal_autoclosable: close on highlighting text

[rtemision]

If you start highlight text and stopping the highlighting outside of elem content then in the pointerclick event.target will be the parent node of the content element, and as a result the modal closes.

Here can be repeated: hold down mouse button and with the mouse movement highlight the text in title or input/textarea from left to right and let go of the mouse button the mouse button outside the content element - modal closes. In Firefox, it is not always possible to repeat with input and textarea, but with simple text regularly, in Chrome - without much difference.

[rtemision]

As a temporary fix, I’m comparing event.target from pointerdown and pointerup.