title: changing tableview height at runtime
body: <p>Hlo,
  I'm creating a menu as a tableview and toggling its visibility on button click. I'm changing its height actually.But changing the height of tableview is affecting only tableview not the cells inside it. TableView also have shadow, if i remove shadow it works perfectly. Please help.
  Here is some code fragment</p>
  
  <pre><code>let _initialTableFrame = CGRectMake(self.view.frame.size.width - 150, 68, 140, 0)
      _topMenuTableView = UITableView(frame: _initialTableFrame)
      _topMenuTableView.delegate = self
      _topMenuTableView.dataSource = self
      _topMenuTableView.rowHeight = 35
      _topMenuTableView.tag = 100
      _topMenuTableView.alpha = 0.9
      _topMenuTableView.tableFooterView = UIView()
      _topMenuTableView.scrollEnabled = false
  
      _topMenuTableView.layer.cornerRadius = 5
      _topMenuTableView.layer.shadowColor = UIColor.blackColor().CGColor
      _topMenuTableView.layer.shadowOffset = CGSizeMake(0, 0)
      _topMenuTableView.layer.shadowRadius = 5.0
      _topMenuTableView.layer.shadowOpacity = 1 
  func toogleTopMenu()
  {
      if _isTopMenuVisible
      {
          let _currentTopMenuFrame = _topMenuTableView.frame
          let _tempFrame = CGRectMake(_currentTopMenuFrame.origin.x, _currentTopMenuFrame.origin.y, _currentTopMenuFrame.size.width, 0)
  
  
          UIView.animateWithDuration(0.2, animations: {self._topMenuTableView.frame = _tempFrame})
          _isTopMenuVisible = false
      }
      else
      {
          let _currentTopMenuFrame = _topMenuTableView.frame
          let _tempFrame = CGRectMake(_currentTopMenuFrame.origin.x, _currentTopMenuFrame.origin.y, _currentTopMenuFrame.size.width, 38)
  
          UIView.animateWithDuration(0.2, animations: {self._topMenuTableView.frame = _tempFrame})
          _isTopMenuVisible = true
      }
  }
  </code></pre>