I'm just asking what causes that to happen, when I know that a screen ultimately consists of x*y pixels that keep updating as long as the PC screen is turned on. And if the program terminates, then what keeps updating the pixels on the screen? It sure ain't a terminated program.
Not that it matters here but in actuality I wouldn't say that's true at all.
The monitor keeps the light on in its pixel crystals constantly, and updates their colors in frequent intervals of for example 60 times per second.
The monitor chooses the colors to update to from a signal that comes from the computer through the cable.
The signal is generated from the values of some memory in the graphics card.
If a color value is written to that memory it stays there until over-written or the power is turned off, so on the software side it's more that a pixel stays the same on the screen until it is actively changed in memory by a running program.
Then in actual actuality it's probably somewhat different again and depends on many things but I don't even know.