diff --git a/core/misc/dialog/dialog.position.js b/core/misc/dialog/dialog.position.js
index 358c382..4a4e2e8 100644
--- a/core/misc/dialog/dialog.position.js
+++ b/core/misc/dialog/dialog.position.js
@@ -59,8 +59,8 @@
     // If we are not adjusting height but are adjusting min/maxHeight we need to
     // set height property to 'auto'. If height is not set to 'auto' jQuery UI
     // dialog _size() will ignore min/maxHeight attribute.
-    if (!adjustedOptions.hasOwnProperty('height') && (adjustedOptions.hasOwnProperty('minHeight') || adjustedOptions.hasOwnProperty('maxHeight'))) {
-      adjustedOptions['height'] = 'auto';
+    if (!adjustedOptions.height && (adjustedOptions.minHeight || adjustedOptions.maxHeight)) {
+      adjustedOptions.height = 'auto';
     }
 
     // Offset the dialog center to be at the center of Drupal.displace.offsets.