Create a VisualForce page for only classic

Question

I would like to create a VisualForce page that shows on a Contact record, however, I only want it to show while the user is in Classic mode. I have tried using $User.UIThemeDisplayed to render the wrapping apex:outputPanel depending on if the User is in Classic or Lightning. However, while in Lightning this results in a massive block of whitespace where I would like for the space to not even be allotted to the page.

UPDATE: I tried to simplify my page but I realize that the previous example actually behaves exactly how I want it to. What I am also doing in my page is using Lightning Out to display a custom Lightning component for classic. My hope is that this VisualForce page only shows in classic and that I can use the custom Lightning component as it's own tab in the Lightning experience.

<apex:page standardController="Contact" standardStylesheets="false">
  <apex:outputPanel rendered="{!$User.UIThemeDisplayed == 'Theme3' }">
      <apex:stylesheet value="{!URLFOR($Resource.SLDS202, 'assets/styles/salesforce-lightning-design-system-vf.min.css')}" />
      <apex:includeScript value="/lightning/lightning.out.js" />
      <div id="lightning" />
      <script>
          var contactId = "{!Contact.Id}";
          $Lightning.use("c:MyApp", function() {
              $Lightning.createComponent("c:RelationshipWidget",
              { recordId : contactId},
              "lightning",
              function(cmp) {});
          });
      </script>
  </apex:outputPanel>
</apex:page>

Answer 1

You can also uncheck the value "visualforce page available for Lightning and mobile experience" in setup->visualforce pages

you wont have to detect theme, add to the classic layout: it will show in classic and will not show in lightning

Answer 2

There is currently a Known Issue: Spring '17 Visualforce Pages appearing in Lightning when not flagged to do so.

Unchecking the "Available for Lightning Experience, Lightning Communities, and the mobile app" doesn't always work.