I've been a DF user for years and love it. Buty latey I've been having trouble with apps like FF and Outlook switching from one monitor to aother when the app starts. This happens in the morning when I power on my docked laptop. I'll start Outlook then while Outlook is comming up on the correct monitor, I'll start FF. FF lives on my second monitor and usually starts there. But what will happen is Outlook will on it's own, flip to the other monitor, or FF will flip to the main monitor. It's a bit frustrating to have to manually move everythnag back. I'm on DF Pro 11.1.1 on WIN 10 22H2

I do have the multi-monitor taskbar enabled. I'll disable it and see if it makes a difference. It might a day or two to get back to you. Thanks for the idea!

So far so good. No isues with apps flipping yesterday or today. Keeping my fingers crossed.

Well, this morning when I started the PC, I started Outlook first and it came up on the main monitor(right) which is correct. I then started FF right after that. I saw a brief flash on the left monitor and FF came up on the main monitor (right) instead. I had to manually switch it to the left monitor. Outlook takes a several seconds to start on my system. So it was still "starting up" when I started FF.

I tried another test. I left FF on the left monitor and exited Outlook. I then started Outlook again, and during the Outlook startup process, FF switched monitors without any input from me. I think we may have discovered something. The Outlook startup process is triggering the montitor switch if FF is running. I also noticed the FF seems to prefer the right monitor after this happens.

I tried the same using Chrome vs FF and there was no switching. Chrome stayed put.

If I terminate the DisplayFusion process, the windows works normally. I can start Outlook and FF literally at the same time and the go to the correct monitors and stay there. If I exit Outlook and FF and restart DisplayFusion, the issue comes back. It's actually pretty easy to duplicate.