no flash

in a user interface design, by default when transition from one screen to the next

or when a new application is launch. there should be a smooth transition, no flashing, blink, or any sort of visual que that might distract the user

for reasons, I can not explain, lately, I notice unusual screen behavior (the kind of electronic screen driven by electricity) in ... 

one clearly notice able artifact is a flash, a blink, sometimes the entire screen, sometimes, only the specific area (territory) of the application window would flash; 

it is like, but it is not like; if you have never to a place (people, places, thigns, processes, procedures, protocols, ... ) before, how can you tell, the environment is normal (that this is the baseline environment); ...