Editing UITableView - iOS Programming: The Big Nerd Ranch Guide - page 316

In HeaderView.xib , select the File's Owner object and change its Class to Item-
sViewController in the identity inspector ( Figure 10.4 ).
Figure 10.4 Changing the File's Owner
Drag a UIView onto the canvas. Then drag two instances of UIButton onto that view.
Resize the UIView and make the connections shown in Figure 10.5 .
Figure 10.5 HeaderView XIB layout
Also, change the background color of the UIView instance to be completely transparent.
To do this, select the view and show the attributes inspector. Click the color picker labeled
Background to show the color wheel and then drag the Opacity slider to 0 ( Figure 10.6 ).
Figure 10.6 Setting background color to clear