Skirmish mode starts with a bot selected.

OpenRA.Game/Network/Session.cs

@@ -31,6 +31,12 @@ namespace OpenRA.Network
 			return Clients.SingleOrDefault(c => c.Slot == slot.Index);
 		}
 
+		public int FirstEmptySlot()
+		{
+			return Slots.First(s => !s.Closed && ClientInSlot(s) == null
+			                   && s.Bot == null).Index;
+		}
+
 		public enum ClientState
 		{
 			NotReady,

OpenRA.Game/Server/Server.cs

@@ -216,7 +216,7 @@ namespace OpenRA.Server
 
 				// Enforce correct PlayerIndex and Slot
 				client.Index = newConn.PlayerIndex;
-				client.Slot = ChooseFreeSlot();
+				client.Slot = lobbyInfo.FirstEmptySlot();
 				
 				var slotData = lobbyInfo.Slots.FirstOrDefault( x => x.Index == client.Slot );
 				if (slotData != null && slotData.MapPlayer != null)
@@ -235,13 +235,6 @@ namespace OpenRA.Server
 			}
 			catch (Exception) { DropClient(newConn); }
 		}
-
-		int ChooseFreeSlot()
-		{
-			return lobbyInfo.Slots.First(s => !s.Closed && s.Bot == null 
-				&& !lobbyInfo.Clients.Any( c => c.Slot == s.Index )).Index;
-		}
-		
 		
 		public static void SyncClientToPlayerReference(Session.Client c, PlayerReference pr)
 		{

OpenRA.Game/Widgets/WidgetUtils.cs

@@ -199,6 +199,8 @@ namespace OpenRA.Widgets
 			}
 			return text;
 		}
+
+		public static Action Once( Action a ) { return () => { if (a != null) { a(); a = null; } }; }
 	}
 
 	[Flags]