Maybe this question fits better in FML category.  I would like to select specific posts for display.  I'm guessing the "Single Post" widget will do something along that line. However the Single Post Widget requires a "Single Post ucid."  What is a ucid and where do I find it?

When I attempt to create a "Single Post" widget the error: "Single Post Invalid post ucid from the tab:" shows up.  I've tried pasting numbers like 0C7EEFFFF009F801300090020E1E4 from the URL of discussion posts, I've also tried numbers from video clips, I've tried a number I found in a widget where communityUcid= but all these attempts generate the same error message.