title: How to hide completely a QGridLayout?
body: <p>I have a button followed by a <code>QGridLayout</code> full of widgets.
  I want to show/hide <code>QGridLayout</code> at every button click, but reading documentation of <code>QGridLayout</code> I see there's no <code>show()</code>/<code>hide()</code> implementation, also no <code>setVisible()</code> method available.</p>
  
  <p>How do I achieve this?</p>