diff --git a/res/Resource.cs b/res/Resource.cs
index 65f4431..6d9f08f 100644
--- a/res/Resource.cs
+++ b/res/Resource.cs
@@ -24,7 +24,7 @@ public interface Res_old
 }
 
 [DebuggerDisplay("Path = {path}")]
-public class Ref : lib.I_Serialize
+abstract public class Ref : lib.I_Serialize
 {
 	static public bool s_verboseLogging = false;
 
@@ -47,13 +47,13 @@ public class Ref : lib.I_Serialize
 		_dbgLine = dbgLine;
 	}
 
-	virtual public object lookup(
+	abstract public object lookup(
 													string reason = "",
 													[CallerMemberName] string dbgName = "",
 													[CallerFilePath] string dbgPath = "",
 													[CallerLineNumber] int dbgLine = 0
 
-	) => default;
+	);
 
 
 	virtual public void OnChange()
@@ -116,12 +116,13 @@ public class Ref<T> : Ref where T : class, new()
 		base( !string.IsNullOrWhiteSpace(filename) ? filename : $"{{{dbgName}_{log.whatFile(dbgPath)}}}" , reason, dbgName, dbgPath, dbgLine )
 	{
 		if( s_verboseLogging ) log.info( $"Ref {GetType().Name} {GetType().GenericTypeArguments[0]} path {Filename}" );
+		m_res = default;
 	}
 
 
 	override internal void load()
 	{
-		m_res = Mgr.load<T>( Filename, _reason, _dbgName, _dbgPath, _dbgLine, _dbgExp );
+		m_res = Mgr.load<T>( Filename, _reason, _dbgName, _dbgPath, _dbgLine );
 		if( s_verboseLogging ) log.info( $"Ref.load {GetType().Name} {GetType().GenericTypeArguments[0]} path {Filename}" );
 	}
 
@@ -161,23 +162,20 @@ public class Ref<T> : Ref where T : class, new()
 	}
 
 	[NonSerialized]
-	protected T m_res;
+	protected T? m_res;
 }
 
 public class Resource
 {
-	static public Mgr mgr;
+	static public Mgr mgr = new();
 }
 
 public delegate T Load<out T>( string filename );
 
 
-class LoadHolder
+abstract class LoadHolder
 {
-	internal virtual object load()
-	{
-		return null;
-	}
+	public abstract object load();
 }
 
 
@@ -190,7 +188,7 @@ class LoadHolder<T> : LoadHolder
 
 	public Load<T> _fnLoad;
 
-	internal override object load()
+	public override object load()
 	{
 		return load();
 	}
@@ -212,9 +210,9 @@ class ResCache<T> where T : class, new()
 
 public class Mgr
 {
+
 	static public void startup()
 	{
-		Resource.mgr = new Mgr();
 	}
 
 	static public void register<T>( Load<T> loader )
@@ -266,7 +264,7 @@ public class Mgr
 
 						var lh = Activator.CreateInstance( lhType, loader ) as LoadHolder;
 
-						ImmutableInterlocked.TryAdd( ref Resource.mgr.m_loaders, t, lh );
+						ImmutableInterlocked.TryAdd( ref Resource.mgr.m_loaders!, t, lh );
 					}
 				}
 				return;
@@ -319,13 +317,11 @@ public class Mgr
 	}
 	*/
 
-	static public T? load<T>( string filename,
+	static public T load<T>( string filename,
 													string reason = "",
 													[CallerMemberName] string dbgName = "",
 													[CallerFilePath] string dbgPath = "",
-													[CallerLineNumber] int dbgLine = 0,
-													[CallerArgumentExpression("fn")]
-													string dbgExp = default
+													[CallerLineNumber] int dbgLine = 0
 	 ) where T : class, new()
 	{
 		if( ResCache<T>.s_cache.TryGetValue( filename, out var holder ) )
@@ -373,7 +369,7 @@ public class Mgr
 				{
 					var loader = loaderGen as LoadHolder<T>;
 
-					var v = loader._fnLoad( filename );
+					var v = loader!._fnLoad( filename );
 
 					var weak = new WeakReference<T>( v );
 
@@ -408,7 +404,7 @@ public class Mgr
 	static ImmDefLoad s_deferredLoad = ImmDefLoad.Empty;
 
 
-	Mgr()
+	public Mgr()
 	{
 		log.info( $"Creating Res.Mgr" );