Description
        This test validates that the page properly becomes hidden and visible due to switching tabs.
        Manual Test Steps:
        
            
                -  Ensure this page is the foreground and click the "Start Test"
-  Switch to another tab
-  Return to the current tab containing this test page
Note: This test will automatically timeout and fail if not completed within 60 seconds.
        IFrame with default style:
        
        
        
        IFrame with "display:none" style: