Ensure only one information overlay is open at once

osu.Game/OsuGame.cs

@@ -255,6 +255,22 @@ namespace osu.Game
                 };
             }
 
+            // eventually informational overlays should be displayed in a stack, but for now let's only allow one to stay open at a time.
+            var informationalOverlays = new OverlayContainer[] { beatmapSetOverlay, userProfile };
+            foreach (var overlay in informationalOverlays)
+            {
+                overlay.StateChanged += state =>
+                {
+                    if (state == Visibility.Hidden) return;
+
+                    foreach (var c in informationalOverlays)
+                    {
+                        if (c == overlay) continue;
+                        c.State = Visibility.Hidden;
+                    }
+                };
+            }
+
             settings.StateChanged += delegate
             {
                 switch (settings.State)