This is an age old issue I have with display fusion.
If i disable or enable "Enable Multi-Monitor Taskbars" I see the extra icons menu from the taskbar is out of place.
I have a split my screen into 3 parts. It seems the menu shows up at the bottom righ of the middle or second screen.
Does this happen for a few seconds after the setting has been adjusted, and then fixes itself?
No it seems what happens is the middle split is autofocused when I click on the arrow to show the menu in the right split and so the menu shows in the middle split.
If i click on the toolbar first to focus the split and then click on the arrow to show the menu it shows in place.
Also I have downgraded from the latest DF to 9.9 which has solved various problems for me including this one.
One thing i noticed is that 9.9 installer also installs a .net package 10.1 Beta2 and 10.0 dont.