I'm using classic shell 4.3.1, display fusion 9.3 on steam and I have windows 10 Home. If I do not have some kind of window on my primary monitor the start menu will just go behind whatever window that is there on the second monitor. Games no matter if full-screen or borderless will not affect the issue. The Recording is exactly what the issue is in action and is 100% repeatable ( sorry for watermark just wanted something to snip the video). I cleared my log and started a new one and instantly did the issue a couple of times.

What ever I can do to assist you in fixing the issues

Yea looks like you did what I did to recreate it. However, with me messing around in classic shell I found out that if you open the classic shell settings and it pops up on your primary monitor then click ok. The issue is fixed until a new window appears on your primary monitor and you close it. I don't know if this helps or not lol but its what I figured out.

I'm back and with a soultion. I found an old forum from Classic shell that gave a link to a tool to "keep taskbar on top".https://www.csparks.com/Win7TaskbarMasher/ .This is what works for me but it would also be nice for something like this to be integrated as an option in Displayfusion. Since apparently others are having this issue too.

Yea I got you the link to the old post.http://www.classicshell.net/forum/viewtopic.php?f=13&t=583

Just wanted to add that I have this issue as well. Running Windows 10 Enterprise v1909 with Display Fusion 9.7 Beta 6. I've got OpenShell v4.4.142. Running the Win7TaskbarMasher app fixes the issue. Don't mean to revive a dead thread, but glad I found a fix!