I've been playing with developing a similar block-based editor, this was some tremendous inspiration in terms of UI and functionality. I especially like how blocks are rendered until you click on them, and they re-render when you blur the markdown input field. Being able to inject data sources into the document is brilliant. I really appreciate you open-sourcing your work, and I will definitely do the same with mine!<p>One thing we are both doing is relying heavily on icons to indicate the different kinds of blocks that can be added. To make the role of each icon more apparent, I added a tooltip on hover. This may be useful here as well, e.g. for the code blocks there is an icon that cycles between fa-refresh and fa-users that I didn't immediately understand.<p>Thanks again for this fantastic contribution!