I've merged the user interface from the "native" version with the web version.

You may notice some changes from the traditional JCS:
The select box for Tile Type, Events, Mask and (none) have been replaced with four toggle buttons, Image, Mask, Tile Type, and Events. If both Image and Mask buttons are pressed down, you will get the masked view but with the image visible above it, intersected with the mask. It fades when you switch the view See below or try the demo!
Todo next: a class/manager for the layer view.

Live demo: http://djazz.mine.nu:8011/