The designer looks very promising. The properties handling looks way easier than the designer from sencha.
What’s missing is the “events part”. It would be great to have a how-to documentation (videos?) on how to handle the most important events with “real world examples” in order to have a good staring point to bring a DHTMLX application to life. The better this documentaion is, the more successful your tool will be.
There are many people out there used to work as designer and part-time programmer but do not have the skills and time to hard-code all the needed listerners and handlers by themselves.
Maybe you do also put-up a skill database where users can also add solutions how they implemented handlers and listerners.