Just updated to DF 5.1 and now my process explorer tray icons show a magnifying glass over windows flag icon instead of the proper icons.

They were working in the past with Beta 13 or so.

That's what the Process Explorer icon looks like: a Windows flag with a magnifying glass over it. What did yours look like before? Did you somehow set a custom icon for it?

Normally Process Explorer has two system Tray Icons enabled on my system - I/O History and CPU History, which show tiny graphs of the corresponding history. Previously the DF taskbar showed the tiny graphs just like the Win7 taskbar.

Oh, sorry, I was thinking taskbar icons for some reason. I can confirm the tray icons work on Beta 13. I don't have the latest version installed yet.
Edit: The tray icons work for me in 5.1. When I enable a tray icon, it briefly shows up as the Process Explorer icon. After a second or two, it changes to the graph.

I use a local administrator account.

It seems to have cleared up at the same time the Start Menu/primary monitor issue also cleared up - I restart Process Explorer now and DF taskbar immediately shows the correct icons.

Thanks!