I'm using the most up-to-date Visual Studio 2017 Preview, and I've tried uninstalling and resetting the settings, however this spacing continues regardless of what I do.
How can I remove this?
See the image below:
Usuallythese"gaps" between the lines are "helpers" that the editor shows, things that they want to show but which are not really written in the code.
Check your syntax highlighting properties and options. It may be that in your case these "helpers" are being written with the same background color and so you do not see them.