title: Hook standard Inno Setup checkbox
body: <p>I added an InputOptionWizardPage for selecting tasks. This works fine, but I would like to add some custom functionality. One task is dependent on the other, so if the second checkbox is checked, the first should be checked and grayed out.</p>
  
  <p>To do this, I need to access the properties of a checkbox. I found ways to do this using a completely custom page, where I would explicitly create the checkbox myself, but that would be a lot of work, since most of what I have so far is satisfactory.</p>
  
  <p>How can I hook a checkbox that was created by Inno Setup, using <code>MyInputOptionWizardPage.Add('This will add a checkbox with this caption')</code>?</p>