public HNodeBlockUpdated(LevelSession parent, Block oldBlock, Block newBlock, int index)
     : base(parent)
 {
     this.oldBlock = oldBlock;
     this.newBlock = newBlock;
     this.index    = index;
 }
 public HNodeCollUpdated(LevelSession parent, Collision oldCollision, Collision newCollision, int index)
     : base(parent)
 {
     this.oldColl = oldCollision;
     this.newColl = newCollision;
     this.index   = index;
 }
 public HNodeObjAdded(LevelSession parent, LevelObject addedObj, int index, OBJECT_CATEGORY list)
     : base(parent)
 {
     this.addedObj = new LevelObject(addedObj);
     this.index    = index;
     this.list     = list;
 }
 public HNodeDecoUpdated(LevelSession parent, Decoration oldDeco, Decoration newDeco, int index, DECO_CATEGORY list)
     : base(parent)
 {
     this.oldDeco = oldDeco;
     this.newDeco = newDeco;
     this.index   = index;
     this.list    = list;
 }
 public HNodeObjUpdated(LevelSession parent, LevelObject oldObject, LevelObject newObject, int index, OBJECT_CATEGORY list)
     : base(parent)
 {
     this.oldObj = new LevelObject(oldObject);
     this.newObj = new LevelObject(newObject);
     this.index  = index;
     this.list   = list;
 }
 public HNodeLevelPropertiesUpdated(LevelSession parent, LevelProperties oldProperties, LevelProperties newProperties)
     : base(parent)
 {
     this.oldProperties = oldProperties;
     this.newProperties = newProperties;
 }
 protected InternalHistoryNode(LevelSession parent)
 {
     this.parent = parent;
 }