I hidden the taskbar on the secondary monitor, but I'm unable to restore it. How do I restore it?

Try right clicking on the DF icon on your main taskbar and select "Settings".
Click on the "Taskbar" tab in the window that opens then make sure there is a checkmark in the top box - "Enable Multi-Monitor Taskbars..............

You did turn it off in DF didnt you?

Wow, support of a Sunday. Cheers, thanks! I did do that already. No success. I'm pretty sure I hid the taskbar via DF.

Oops, my bad. Hidden via Windows, and not DF. Fixed. My apologies!