The files that your browser has downloaded is called a cache.
When this happens, since Sprout Studio is looking for the new files but gets the old ones from your browser, it results in Sprout not looking or functioning the way it should.
If you are seeing images rendering weird, if the design of Sprout Studio is looking off, or if you are getting an error while trying to do something in Sprout Studio, this is typically the culprit, especially if we have recently released an update.
You should first try hard-refreshing:
Click Control-F5 if you are on Windows
Click Command-Shift-R if you are on Mac OS
If that doesn't solve the problem, try clearing your cache. Here is a page that shows you how to clear your cache on many of the most popular internet browsers.