twitter/bootstrap — pull request #7113 by olahol (2013-03-01 12:29:15+00:00)
Title: dropdown events 'show' and 'hide'

Small patch that adds "show" and "hide" events on dropdowns. Useful for notification
systems that track seen notifications. Related to issue #1343.

Usage:
```js
$('#myDropdown").on('show', function () {
// code
})

$('#myDropdown').on('hide', function () {
// code
})
```

Tested with Firefox 14.0.4 and Google Chrome 21.0.1180.81 on Ubuntu 12.04