I, too, Jackie, thought it might have to do with a sideman character in a minstrel show. But one of the most famous sideman monickers is "Mr. Bones" and I've never heard of anyone associating that term with racial disparagement. And, then, I think, perhaps, there was a time when the term "sunshine" was used as a sort of inverted slur for Negroes because they were dark. As when someone is glum and you say, "How's it goin', happy?" It was definitely an insult in that context...but in those days they were just supposed to grin and bear it, as if it were a joke or friendly chide. In fact, I seem to recall Bing Crosby, of all people, saying this to a black character in a movie somewhere circa the 1940's...something akin to "How ya doin' today, sunshine!" So you can imagine how foolishly tame it was considered then. Does this trigger anybody else's memories along these lines? 'Cause, now, I'm pretty sure that's it.

Welcome Dotman_ga! For all that I've said, "Mr. Sunshine" sounds like it has a lot of ambiguity attached to it. And that someone is really digging to start trouble over this one. Now, I'm afraid, it's become a tool to a means in many cases, rather than genuine injury. Stick around! An intriguing post!