Widget: _bind() on elements such as document are dangerous

[scott.gonzalez]

If all instances of a widget are binding to a common element, such as document, then when one instance of destroyed all event handlers will be unbound. This is problematic and needs to be addressed somehow.

[scott.gonzalez]

One thought is that we can just be aware of the problem and avoid doing this. It's not specific to _bind() anyway. We'd need to have a single event handler that manages all instances. We could potentially make this easier by having the widget factory automatically track all instances. This shouldn't be too bad in terms of memory since it's just an array of pointers. For example, right now we're  tracking all droppable instances in the interactions rewrite. We could just automatically track this in $.ui.droppable.instances.

[scott.gonzalez]

Suggestion from gnarf: Create a uuid for all instances and use the uuid in the namespace inside _bind().

[joern.zaefferer]

Adding a uuid to the namespace is also what Backbone's delegateEvents method does:  http://documentcloud.github.com/backbone/docs/backbone.html#section-156

Note eventName += '.delegateEvents' + this.cid;

[joern.zaefferer]

Here's a test:  https://gist.github.com/7325217f7f3c78f45457

[joern.zaefferer]

PR:  https://github.com/jquery/jquery-ui/pull/676

[Jörn Zaefferer]

Generate a uuid for each widget for unique namespaces. Fixes #8385 - Widget: _bind() on elements such as document are dangerous

Changeset: 28b14ec47cfeb3c58e44f35170cdd8a9270aceae