title: Only allowing one checkbox to be checked for a userform
body: <p>So I'm making a userform and I have to use make a group of mutually exclusive checkboxes or only allow the user to pick one. "But just use option buttons!" you cry. Two problems with that:</p>
  
  <ol>
  <li><p>I already have a separate set of option buttons in the userform (I believe you can somehow group them to allow multiple sets but I am unfamiliar with how to actually do this). </p></li>
  <li><p>My professor specifically wants checkboxes </p></li>
  </ol>
  
  <p>so I attempted to solve this problem like this</p>
  
  <pre><code>If CheckBoxBar.Value = True And CheckBoxatm.Value = True Then
  GoTo Here:
  End If
  
  If CheckBoxatm.Value = True And CheckBoxmmHg.Value = True Then
  GoTo Here:
  End If
  
  If CheckBoxatm.Value = True And CheckBoxpsia.Value = True Then
  GoTo Here:
  End If
  
  If CheckBoxBar.Value = True And CheckBoxmmHg.Value = True Then
  GoTo Here:
  End If
  
  If CheckBoxBar.Value = True And CheckBoxpsia.Value = True Then
  GoTo Here:
  End If
  
  If CheckBoxmmHg.Value = True And CheckBoxpsia.Value = True Then
  GoTo Here:
  End If
  </code></pre>
  
  <p>The here leads to a message box that re initializes the userform after the msg box says "You are only allowed to select one" with code like this</p>
  
  <pre><code>Here: MsgBox "You are only allowed to select on pressure unit."
  </code></pre>
  
  <p>The code "works" but it always goes to the Here: statement despite only picking one of the checkboxes. Can you spot anything wrong?</p>
  
  <p>Thanks for the help!</p>