On wake, my Dreamcolor Z24x G2 display shows the desktop in a small 5 x 2" window in the top left

[Huemancer]

My DreamColor Z24x G2 display is persistently waking up with a small window in the upper left showing the desktop. (I've attached a photo to show what I mean.) I can "fix" it by opening the monitor's menu and doing a Factory Reset. But then it shows up the next day the same as before. I've been searching for days for a solution to no avail, so here I am. 

Before this, I did have some very strange problems. You can read about that here. I needed to reinstall Win 11 from scratch to fix it. That means, of course, if my current problem is software-related, it shouldn't be connected to my previous problem. But that doesn't rule out a hardware problem. If so, I don't know how to track that down. 

I have run the HP PC Hardware Diagnostic tool, but it found nothing wrong. I ran some basic Win 11 hardware diagnostic tools as well (dxdiag, etc.), with the same results. I'm stumped. I would be very grateful for any assistance with this. Thanks!Tiny desktop

[Huemancer]

Bump, with the hope this catches someone's eye. I could really use some help here. Thanks!

[Huemancer]

Since none of my previous posts to this HP Community forum has generated an answer, I thought I'd try one last time before finally deciding that this forum is useless. Which is a shame as I do very much like HP products. 

An update from my previous post: The picture-in-picture (PIP) error still occurs. And it unfortunately occurs randomly, which makes troubleshooting significantly harder. Yesterday, after about two weeks of blissful error-free use, the PIP error returned.  Being beyond frustrated with the problem, I finally decided to unhook it from my HP workstation (where I'd much prefer to use it) to see how it performs with my Macbook Air. No problems at all! It worked beautifully. 

Until I sat down to the Macbook just now. The Dreamcolor monitor is now only showing in black and white! And the on-screen menus don't work. I press the side buttons and the first menu shows up (Color Space, Input Select, Luminance, Open Menu & Power). But pressing the buttons again to go further does absolutely nothing. 

Any clue? Is the monitor on its way to a quiet death? I would appreciate any help, please.