diff --git a/src/DebugBar/Resources/debugbar.js b/src/DebugBar/Resources/debugbar.js
index 9780aaf8..3b2e6067 100644
--- a/src/DebugBar/Resources/debugbar.js
+++ b/src/DebugBar/Resources/debugbar.js
@@ -425,7 +425,11 @@ if (typeof(PhpDebugBar) == 'undefined') {
             this.activeDatasetId = null;
             this.datesetTitleFormater = new DatasetTitleFormater(this);
             this.options.bodyMarginBottomHeight = parseInt($('body').css('margin-bottom'));
-            this.isIframe = window.self !== window.top;
+            try {
+                this.isIframe = window.self !== window.top && window.top.phpdebugbar;
+            } catch (error) {
+                this.isIframe = false;
+            }
             this.registerResizeHandler();
         },