I've put together some lines of script code that works fine for me to show file name and tags in a popup window. It's based on the button code tbone provided in this thread from leo: Snippet: Enumerating files and metadata tags.
The script isn't working with the automatic diashow. You'll have to select a single file and advance through the folder using system-wide hotkeys for NEXT/PREVIOUS to make the standalone viewer follow the selection in DOpus. Tbone described how he is doing that in this thread: How let the standalone viewer follow the lister selection?. However a more simple solution is working fine for me (single monitor).
The attached Script-AddIn adds a new user command ShowInfo. The command simply shows a popup with information about the current file's name and tags. In fullscreen mode the taskbar will become visible when the popup comes up. You should always close the popup before showing the next image (Alt or Enter keys and left mouse click to popup or image might work for you dependent on your configuration of the standalone viewer).
The script should be considered only as proof of concept. I'm sure tbone or someone else could make something much better out of it.
system-wide Hotkey for Select Next: Select NEXT
dopusrt /cmd Show
system-wide Hotkey for Select Previous:Select PREV
dopusrt /cmd Show
system-wide Hotkey for ShowInfo:ShowInfo
Command.Generic_ShowInfo.js.txt (2.18 KB)