Right-click the mIRC titlebar and uncheck On Top from the context menu.
Alternately from the menubar, uncheck View > On Top

Otherwise you can tap the WinKey on your keyboard to call up the taskbar.

It looks like mIRC's F11 Full Screen is truly full screen, utilizing the screen dimensions and not the desktop area.
If you take mIRC out of Full Screen, it will utilize the desktop area and allow your autohidden Taskbar sliver to be hovered over.

Last edited by Raccoon; 21/06/21 05:17 PM.

Well. At least I won lunch.
Good philosophy, see good in bad, I like!