diff --git a/PreviewExtension/PreviewViewController.swift b/PreviewExtension/PreviewViewController.swift
index b8a3057..98b6877 100644
--- a/PreviewExtension/PreviewViewController.swift
+++ b/PreviewExtension/PreviewViewController.swift
@@ -80,8 +80,8 @@ class PreviewViewController: NSViewController, QLPreviewingController, WKUIDeleg
       fatalError("Unable to load QuickLookJS configuration: \(error.localizedDescription)")
     }
 
-    if let drawsBackground = configuration.drawsBackground {
-      webView.setValue(drawsBackground, forKey:"drawsBackground")
+    if configuration.drawsBackground == false {
+      webView.setValue(configuration.drawsBackground, forKey:"drawsBackground")
     }
 
     super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)