Add code to track if a view has been rendered, fix issue with duplication of the view, I am not sure if this method of tracking that the view has been rendered is correct, but it works for now

Source/NSTableView.m

@@ -2044,7 +2044,9 @@ static void computeNewSelection
       | NSDragOperationLink | NSDragOperationGeneric | NSDragOperationPrivate;
   _draggingSourceOperationMaskForRemote = NSDragOperationNone;
   ASSIGN(_sortDescriptors, [NSArray array]);
+
   _viewBased = NO;
+  _renderedViewPaths = [[NSMutableArray alloc] init];
 }
 
 - (id) initWithFrame: (NSRect)frameRect
@@ -2076,6 +2078,7 @@ static void computeNewSelection
   RELEASE (_selectedColumns);
   RELEASE (_selectedRows);
   RELEASE (_sortDescriptors);
+  RELEASE (_renderedViewPaths);
   TEST_RELEASE (_headerView);
   TEST_RELEASE (_cornerView);
   if (_autosaveTableColumns == YES)
@@ -7087,4 +7090,9 @@ For a more detailed explanation, -setSortDescriptors:. */
     }
 }
 
+- (NSMutableArray *) _renderedViewPaths
+{
+  return _renderedViewPaths;
+}
+
 @end