It's a bit temperamental but very quick and easy to reinstall. When first opened, make sure it is pointing to the correct install. In these days of big monitors, you can blow up some of the quite complex facilities, to a scale where accurately locating buildings/objects is easier. Trying to do it on a 1024x768 screen would be difficult!
With a bit of fiddling around, you can find how to click on the desired bit of the groundplane, then select from the dropdown list of buildings/facilities/objects, and insert quickly at the desired orientation (possibly at a different altitude too, I don't remember).
Another real trap is if you open an existing facility, for example to develop/improve as a renamed stand alone facility, the editor tends to remove the # wildcard symbol when you save your work as an xml file. I don't know if it is a recent bug (Thank you again, MS, for Win8 and Win10
) or always was like it, but if you want to keep the wildcards, you need to go back in Notepad and reinsert them.