title: synchronize two NSScrollView
body: <p>I read the document <a href="http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/NSScrollViewGuide/Articles/SynchroScroll.html" rel="noreferrer">Synchronizing Scroll Views</a>, and did exactly as the document, but there is an isssue.</p>
  
  <p>I want to synchronize a NSTableView and a NSTextView. first let NSTableView monitor NSTextView, and everything is ok when I scroll the TextView, but when I try to scroll TableView, I found that the TableView will jump to another place(maybe backward several rows) at first, then continue to scroll from that place.</p>
  
  <p>This issue still exists even after I let TextView monitor TableView.</p>
  
  <p>anyone know what's the problem? can't I synchronize a TableView and a TextView?</p>
  
  <p><strong>Edited:</strong>
  OK, now I found that the TableView will go back to the place since last scrolling. for example, TableView's top row is 10th row, then I scroll TextView, now TableView's top row is 20th row, and if I scroll TableView again, the TableView will go back to 10th row first, then start to scroll.</p>