I am still having issues with this in 4.8, leading to either UMG widget classes being broken and not openable anymore or entire editor/game crashes. How can an issue like this not be properly fixed for over a year? 
I am still having issues with this in 4.8, leading to either UMG widget classes being broken and not openable anymore or entire editor/game crashes. How can an issue like this not be properly fixed for over a year?