When I'm closing an app, and the dock is about to refresh the app icon (from opened to closed), and the cursor is in the area of the dock, a splitting glitch happens as show in the picture below. For less than a second. But it's quite ugly and annoying.
Is there any procedure to take that may solve such GUI-related issues on macOS Sierra?
My specs: 13" Retina MacBook Pro (late-2013) 2.4Ghz Intel Core i5, 8gb RAM, Intel Iris 1536MB, macOS Sierra 10.12.2