On 21/03/2021 18:36, Andrew wrote:
On 21/03/2021 18:20, Roger Mills wrote:

No response so far from the Windows community - maybe uk.d-i-y can help?

-------- Forwarded Message --------
Subject: Odd screensaver behaviour
Date: Sat, 20 Mar 2021 23:12:05 +0000
From: Roger Mills
Organization: Association of Revolting Peasants
Newsgroups: alt.comp.os.windows-10

I've just set up a new W10 desktop machine with two monitors - the
main one landscape for general use and the second one portrait for
displaying A4 sized documents in actual size. For obvious reasons, the
monitors are configured as "Extended these displays" rather than
"Duplicate these displays".

I've set up a screensaver in the form of a photo slide show. When the
portrait monitor is on the right and the screensaver cuts in, its
screen goes blank and the slideshow takes place on the main
(landscape) monitor - which is fine.

However, when the portrait monitor is on the left and the screensaver
cuts in, the photos are half on each monitor with black space outboard
of them.

Anyone come across this, and any suggestions for fixing it? [OK I
could put the portrait monitor on the right but I really *want* it on
the left].

How does Windows know where you monitors are ??.

See Steve Walker's answer to that.

The odd thing is that if I lie and tell it that the portrait monitor is
on the right even though it's really on the left, the screensaver works ok.

But then the mouse cursor doesn't move from one monitor to the other in
the way it should.

But why the difference in behavior depending on which way round (it
thinks) the monitors are?

If Windows is treating both as one big monitor, having one in
landscape and t'other in portrait is going to confuse it anyway,
surely ?.

It works ok for most apps - you can move then from monitor to monitor
and resize them to suit or even (less satisfactorily) have then
straddling monitors. Straddling is what the screensaver does with the
monitors one way round but not the other way. Why?

I suspect it may depend on which is the "main" monitor - but don't
understand why.
--
Cheers,
Roger