I have been using Zettlr for a few days now and the experience has been awesome.
I, however, would like to suggest a feature that I think would be very essential, and that's a Markdown Preview window. Rather than having the markdown tags and the preview in one window, we could have a window for each one, or at least have the Quick Lookup option show a Markdown preview that has not Markdown tags.
I seem to have issues with previewing tables in Markdown with the current way that Zettlr is setup, the tables seem to easily break apart. A separate window for Markdown tags and MArkdown preview in my opinion will fix this.
I just attached a picture for better clarity.