Hi,
I just had this issue after updating to 6.9 yesterday. I could only click on items in the dashboard tab, almost nothing was clickable on any other tabs, including diagnostics
However, I managed to fix it by updating all plugins as the "Update All Plugins" button luckily still worked for me.
I have a feeling it was the Unraid.net Plugin, but I am not sure exactly.
Hope that helps you.