The age-old story on a stalled film adaptation of August Wilson’s award-winning play Fences is that, the playwright insisted to the studio (Paramount Pictures at the time – this was in the late 1980s) that the director of the film be black.  Of course, Paramount didn’t feel that was necessary, stating that they wanted “the best director for the job.” Even Eddie Murphy, who was then attached to star in and co-produce the film adaptation, told Wilson that he wasn’t going to hire a director just because they were black. 
Wilson reiterated that he wasn’t suggesting that a black be director hired simply because they are black, but certainly a black director who was qualified for the job. But this wasn’t a clause in the original agreement between Wilson and Paramount, so the studio wasn’t legally bound to adhere to Wilson’s wishes (however they realized well enough that a film adaptation of Fences without Wilson’s blessing, wasn’t something that they wanted to do). While seeming to be taking Wilson’s wishes under strong consideration, the studio approached Barry Levinson to helm the film; obviously, Levinson isn’t black. 
Needless to say, Wilson didn’t approve. Although Levinson backed away from the project anyway, after he saw the play himself, stating that he didn’t think it would translate well to the screen – at least, not the version of the script that Wilson had written. Wilson’s public objections to a white director helming the project were also of some influence.