Modal Sometimes Does Not Appear after Multiple Displays in Safari

Created by: jayhaase

Displaying, hiding, and displaying the same modal multiple times will sometimes fail, leaving the modal backdrop fade in place and no modal displayed.

This has been reproduced in Safari.

Steps to reproduce:

1. Go to this page: http://getbootstrap.com/javascript/#modals
2. Click on the "Launch modal demo" button 10-20 times.
3. You have reproduced this error is the dialog does not appear at least once.