And perhaps something that makes the icons snap to an even grid IF toggled. Sorry, last suggestion.
Awesome work!
One suggestion I have: When I hover over the icons, it gives me a description. It would be nice if it did the same with the props (if you used these for specific purposes). And perhaps the ability to save as you go in case you can't complete your schematic in one sitting.
WONDERFUL job. I'm in awe of this product. :)