New variant of old Windows graphics "window contour trails" bug

This morning, just now, encountered a new variant of an old bug.

I have often run into what I call the Windows contour trail bug: when dragging windows around the screen, they leave a trail of old, partially overwritten, window contents. Looking rather like mouse trails. As if the windw was being redrawn every few fractions of a second, each time overwriting the drawing of the window at its old position, and the background was never replacing the overwritten window contents at the old position. Fills the screen with rather pleasant abstract art.

Unfortunately, a reboot usually seems to be necessary.

Today, same Windows contour trail problem - but on only one monitor. I have 4 monitors connected to that machine. The laptop LCD panel, and 3 USB display adapters. Only one of the monitors, connected to only one of the USB display adapters, has gone buggy.

Which gives a few hints: its not a problem with the overall graphics display infrastructure. Apparently just with one display driver.

... While writing this, apparently fixed itself. Possibly related to going in and out of standby. Possibly related to Windows Explorer desktop shell hanging on a network drive.

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All sorts of thoughts about micro-rebooting running through my head.