Well, the reason I tried to avoid the native alt-tab behavior and attempted the window-manager controlling it was because I had gotten native alt-tab functionality working in an old version of wine (0.9.x), but it gave me the undesirable behavior of the panel always being on top if I alt-tabbed out and resumed focus, which renders the game unplayable for the same reason as the black bar I described, since I can't use that edge of the screen to scroll the game. But I'll try making a separate post to note that issue anyway.
