title: How to know whether NSTableView is in editing?
body: <p>I want to check if my NSTableView is in editing or not.</p>
  
  <p>I tried to use <strong>tableView: shouldEditTableColumn: row:</strong> and <strong>tableView: setObjectValue: forTableColumn: row:</strong> functions. For example:</p>
  
  <pre><code>- (BOOL)tableView:(NSTableView *)tableView shouldEditTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row {
       isRenaming = YES;
       return YES;
  }
  
  - (void)tableView:(NSTableView *)tableView setObjectValue:(id)object forTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row {
       isRenaming = NO;
  
       ...
  
  }
  </code></pre>
  
  <p>However, <strong>tableView: shouldEditTableColumn: row:</strong> function was called even when I didn't try to edit the tableview.</p>
  
  <p>So, sometimes, isRenaming is remained to YES.</p>
  
  <p>How to know whether NSTableView is in editing?</p>