diff --git a/OpenRa.FileFormats/TypeDictionary.cs b/OpenRa.FileFormats/TypeDictionary.cs
index e9c5db5cf5..94c71835cd 100644
--- a/OpenRa.FileFormats/TypeDictionary.cs
+++ b/OpenRa.FileFormats/TypeDictionary.cs
@@ -8,49 +8,73 @@ namespace OpenRa.FileFormats
 {
 	public class TypeDictionary
 	{
-		Cache<Type, List<object>> innerInherit = new Cache<Type, List<object>>( _ => new List<object>() );
+		Dictionary<Type, object> dataSingular = new Dictionary<Type, object>();
+		Dictionary<Type, List<object>> dataMultiple = new Dictionary<Type, List<object>>();
 
 		public void Add( object val )
 		{
 			var t = val.GetType();
 
 			foreach( var i in t.GetInterfaces() )
-				innerInherit[ i ].Add( val );
+				InnerAdd( i, val );
 			foreach( var tt in t.BaseTypes() )
-				innerInherit[ tt ].Add( val );
+				InnerAdd( tt, val );
+		}
+
+		void InnerAdd( Type t, object val )
+		{
+			List<object> objs;
+			object obj;
+
+			if( dataMultiple.TryGetValue( t, out objs ) )
+				objs.Add( val );
+			else if( dataSingular.TryGetValue( t, out obj ) )
+			{
+				dataSingular.Remove( t );
+				dataMultiple.Add( t, new List<object> { obj, val } );
+			}
+			else
+				dataSingular.Add( t, val );
 		}
 
 		public bool Contains<T>()
 		{
-			return innerInherit[ typeof( T ) ].Count != 0;
+			return dataSingular.ContainsKey( typeof( T ) ) || dataMultiple.ContainsKey( typeof( T ) );
 		}
 
 		public T Get<T>()
 		{
-			var l = innerInherit[typeof(T)];
-			if (l.Count == 1)
-				return (T)l[0];
-			else if (l.Count == 0)
+			if( dataMultiple.ContainsKey( typeof( T ) ) )
+				throw new InvalidOperationException( string.Format( "TypeDictionary contains multiple instance of type `{0}`", typeof( T ) ) );
+
+			object ret;
+			if( !dataSingular.TryGetValue( typeof( T ), out ret ) )
 				throw new InvalidOperationException(string.Format("TypeDictionary does not contain instance of type `{0}`", typeof(T)));
-			else
-				throw new InvalidOperationException(string.Format("TypeDictionary contains multiple instance of type `{0}`", typeof(T)));
+			return (T)ret;
 		}
-		
+
 		public T GetOrDefault<T>()
 		{
-			var l = innerInherit[ typeof( T ) ];
-			if( l.Count == 1 )
-				return (T)l[ 0 ];
-			else if( l.Count == 0 )
-				return default( T );
-			else
+			if( dataMultiple.ContainsKey( typeof( T ) ) )
 				throw new InvalidOperationException( string.Format( "TypeDictionary contains multiple instance of type `{0}`", typeof( T ) ) );
+
+			object ret;
+			if( !dataSingular.TryGetValue( typeof( T ), out ret ) )
+				return default( T );
+			return (T)ret;
 		}
 
 		public IEnumerable<T> WithInterface<T>()
 		{
-			foreach( var i in innerInherit[ typeof( T ) ] )
-				yield return (T)i;
+			List<object> objs;
+			object obj;
+
+			if( dataMultiple.TryGetValue( typeof( T ), out objs ) )
+				return objs.Cast<T>();
+			else if( dataSingular.TryGetValue( typeof( T ), out obj ) )
+				return new T[] { (T)obj };
+			else
+				return new T[ 0 ];
 		}
 
 		public IEnumerator<object> GetEnumerator()