Boris Popov recently started asking me about Mootools and has begun playing with. He asked about popups, dialogs, windows, etc.. and luckily I'd already catalogued a lot of the widgets I wanted to add to the Seaside environment with Mootools.
The first and foremost of these is the Mocha GUI components. Here is a screenshot from a collaboration Boris and I did to get Mocha working in Seaside with Seaside-Mootools. The package is in public store as Seaside-Mootools-Mocha. Without Boris's interest and work, this wouldn't have happened so quickly.
The following image shows multiple counters inside Mocha windows.. one of the windows has a specified title, the other does not. The two windows have independent counters, ala the class Seaside example.
Click the image for the full size image