title: Change NSTableView cell value While Editing
body: <p>I want to change the value being displayed in a NSTableView Cell while editing it. My requirement is the following:
  Initially I entered a cell value of 234.5678978 and after editing the value is being rounded up to 0 decimal precision(that means 235). My requirement is that when I could click that cell, it should show me value unto certain decimal precision say up 5 precision, in this case 234.56790). How can I achieve this functionality.
  I tried to capture the action of double click editing the cell of NSTableView:</p>
  
  <pre><code>    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(editingDidEnd:)
                                                   name:NSControlTextDidEndEditingNotification object:nil];
      [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(editingDidBegin:)
                                                   name:NSControlTextDidBeginEditingNotification object:nil];
      [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(editingDidChange:)
                                                   name:NSControlTextDidChangeNotification object:nil];
  
  - (void)editingDidEnd:(NSNotification *)notification
  {
      NSLog(@"text editing fisnished");
  }
  
  - (void)editingDidBegin:(NSNotification *)notification
  {
      NSLog(@"text is being edited");
  }
  - (void)editingDidChange:(NSNotification *)notification
  {
      NSLog(@"text was being changed");
  }
  </code></pre>
  
  <p>But only <code>editingDidEnd</code> was called on tab out and the other two methods were never called. </p>