Add proper encoding decoding for keyed objects

Source/NSTreeController.m

@@ -384,6 +384,8 @@
   self = [super initWithCoder: coder];
 
   if (self != nil)
+    {
+      if ([coder allowsKeyedCoding])
 	{
 	  // These names do not stick to convention.  Usually it would be
 	  // NS* or NSTreeController* so they must be overriden in
@@ -422,6 +424,10 @@
 		      [coder decodeBoolForKey: @"NSSelectsInsertedObjects"]];
 	    }
 	}
+    }
+  else
+    {
+    }
 
   return self;
 }
@@ -429,6 +435,27 @@
 - (void) encodeWithCoder: (NSCoder*)coder
 {
   [super encodeWithCoder: coder];
+  
+  if ([coder allowsKeyedCoding])
+    {
+      [coder encodeObject: _childrenKeyPath
+		   forKey: @"NSTreeContentChildrenKey"];
+      [coder encodeObject:  _countKeyPath
+		   forKey: @"NSTreeContentCountKey"];
+      [coder encodeObject: _leafKeyPath
+		   forKey: @"NSTreeContentLeafKey"];
+
+
+      [coder encodeBool: _avoidsEmptySelection
+		 forKey: @"NSAvoidsEmptySelection"];
+      [coder encodeBool: _preservesSelection
+		 forKey: @"NSPreservesSelection"];
+      [coder encodeBool: _selectsInsertedObjects
+		 forKey: @"NSSelectsInsertedObjects"];
+    }
+  else
+    {
+    }
 }
 
 - (id) copyWithZone: (NSZone*)zone