FIXED: Before this PR, starting a column drag within a scrolled down table would scroll the table content to the bottom (#2753)

Before this commit, in the method [view convertPoint:aPoint toView:aView] : aPoint was not in the coordinate system of view.

AppKit/CPTableHeaderView.j

@@ -550,7 +550,7 @@ var CPTableHeaderViewResizeZone = 3.0,
 - (void)_autoscroll:(CPEvent)theEvent localLocation:(CGPoint)theLocation
 {
     // Constrain the y coordinate so we don't autoscroll vertically
-    var constrainedLocation = CGPointMake(theLocation.x, CGRectGetMinY([_tableView visibleRect])),
+    var constrainedLocation = CGPointMake(theLocation.x, CGRectGetMaxY([self frame])),
         constrainedEvent = [CPEvent mouseEventWithType:CPLeftMouseDragged
                                              location:[self convertPoint:constrainedLocation toView:nil]
                                         modifierFlags:[theEvent modifierFlags]