I have been having the hardest time getting the previewer to work consistently. Before the latest update I was getting mysterious bugs that would prevent it from loading and now it always says: "To use the Xamarin.Forms Previewer, you must first build your project..."
Any tips on how to get this to work? My project builds fine, I've restarted visual studio and opened and closed the files. I've cleaned and rebuilt, including deleting the bin and obj folders.