Navigator Problem

@m1911jim Photoshop relies heavily on your computer's graphics card for rendering previews, applying filters, and smooth UI interactions. When a specific action like moving a slider in a preview window causes a temporary blackout, it often points to a problem with how Photoshop is interacting with your GPU driver or the GPU hardware itself. 

I would first reset Photoshop preferences. Due to crashes, improper shutdowns, disk errors, or even just repeated writes, the preference file can get damaged, leading to erratic behavior in Photoshop. When you reset preferences, Photoshop essentially deletes the old, potentially problematic preference file(s) and creates a brand new one with all default settings. This clean slate can resolve a surprising number of problems. It's important to be aware that resetting preferences will revert all of your personalized settings to their factory defaults. And see if the Navigator no longer blacks out! 

Secondly, I would update the graphics card driver by doing a clean installation of the new driver. Most driver installers offer this option. Once that's done, adjust Photoshop's GPU Settings: Go to Edit > Preferences > Performance (Windows).