I ran into this similar issue a little while ago when trying to fit a scalable video player into dashboard 2. As a test, try removing the auto
(via the browser debug tools) and you will see the space seems normal. I was able to get around this with a little css that I accidentally stumbled across. Also, I had to add an extra container div. Atleast now, I have a custom element that seems to look correct on dashboard 1 and 2. I tried working with your node, but couldn't figure how to update all of that vue stuff to get the stylesheet to do anything, sorry.