Why does a custom cell in the Grouping style always show the default height? I will not use 'heightForRow'

Question

override func viewWillDisappear(animated: Bool) {
    super.viewWillDisappear(animated)
    tableView.estimatedRowHeight = tableView.rowHeight
    tableView.rowHeight = UITableViewAutomaticDimension

}

I would like to use UITableViewAutomaticDimensionto get cell height.

The confused problem is that in the style, the Plainuser cell returns the user height, I use it well UITableViewAutomaticDimension. But in style Grouped, the cell height always returns the default value of 44, and I change the style to Plain, oh no, both return 44 bad. You can try.

And I reset the user cell, style cells Plaincome to life.

I think there is a bug in style Grouped(InterfaceBuilding regardless ...), can anyone help me solve the problem?

I just want to use the style UITableViewAutomaticDimensionin Grouped. By the way, the error shows the ipad and simulator, iphone shows well.

I hope I tell you clearly