Rather than having a FromFolderID property on every single prim and only ever using the root prim one, store on SOG instead.

This reduces pointless memory usage.

OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs

@@ -586,10 +586,21 @@ namespace OpenSim.Region.Framework.Scenes
             }
         }
 
-       /// <summary>
-       /// The item ID that this object was rezzed from, if applicable.
-       /// </summary>
-       public UUID FromItemID { get; set; }
+        /// <summary>
+        /// The item ID that this object was rezzed from, if applicable.
+        /// </summary>
+        /// <remarks>
+        /// If not applicable will be UUID.Zero
+        /// </remarks>
+        public UUID FromItemID { get; set; }
+
+        /// <summary>
+        /// The folder ID that this object was rezzed from, if applicable.
+        /// </summary>
+        /// <remarks>
+        /// If not applicable will be UUID.Zero
+        /// </remarks>
+        public UUID FromFolderID { get; set; }
 
         #endregion
 

OpenSim/Region/Framework/Scenes/SceneObjectPart.cs

@@ -182,8 +182,6 @@ namespace OpenSim.Region.Framework.Scenes
 
         public uint TimeStampTerse;
 
-        public UUID FromFolderID;
-
         public int STATUS_ROTATE_X;
 
         public int STATUS_ROTATE_Y;