Beta Media button disabled after publishing QuickPress post

[lessbloat]

A user that we tested ​stumbled onto this one.

To reproduce:

• From the dashboard publish (or save draft) for a post under QuickPress.
• Then without refreshing the page, try to click the "Beta Media" button.

Actual:

The page scrolls to the top, but the media modal doesn't appear.

Expected:

The media modal should show, allowing you to add images to a second post.

[MikeHansenMe]

I am seeing the same issue. I also noticed when opening the Beta Media (only works on first page load) and inserting an image it never gets added to the post. Not sure if it is related but figured it was worth mentioning.

[azaozz]

When saving the QuickPress postbox/widget is actually reloaded completely with xhr (not sure why). So the event bound to the Add Media button is of course removed. Best way to fix this would be to delegate the click on Add Media. We can also re-attach the event, but ... why go to all the trouble :)

[nacin]

In 22518:

Use event delegation for Add Media, allowing the event to bubble up to #wpbody. Keeps the Add Media button functional on a second use of QuickPress. fixes #22255.