1. Not sure what monitor size you are using, but the right menu blends with the editing area. Would be nice to add a shadow to give me clarity on the division of the right menu.
2. Resize handles on a lot of objects yet I can't resize them.
3. Clicking on the items on the left menu for a preview throws me off. Makes me think that the descriptions are options eg. Page Heading (I tried to drag some of them out a few times).
4. How do I zoom out?
I guess in the context of a Bootstrap toolkit, less is more. I just want to be able to drag stuff and have it all "work". I don't really care about the extra options because the padding, typography, is already taken care of with Bootstrap. That being said I'd want Advanced features to be opt-in.