Is there an example of a browser-based and preferably open source visual javascript application designer (using contenteditable or canvas or whatever), perhaps with support for embedded controls and so forth (checkboxes, buttons, etc., or ui controls for various javascript frameworks like jquery.ui, dojo, yui,...), OR else support for vector graphics and shapes and so forth (canvas/svg vector graphics designer).
One example is ckeditor which has support for inserting html form controls (see the buttons on top right of the editor here): http://ckeditor.com/demo
And dojo's dojox has an example of a crude vector graphics editor ('drawing' I think the library is called).
There are some non-open source, commercial tools or similar tools out there like extjs designer, mockingbird (from cappucino).
And then I've found a few attempts at such things that didn't get too far, like qooxit, blok (using joose), and opus-js.
I have found one nice browser-based designer that is even open source, linb/jslinb, but it is completely undocumented and very complex and server-dependent (and many features are still not implemented yet).
Just wondering if there are any other options/examples out there, too. Thanks.