Consider this scenario, we have a table which gives us the value of a particular product in the first row and the total product value in the last row. Incase we buy just a single product, then the first row value and the last row value remains the same. In this case let us consider you are getting the value of a HtmlText like this,
String value = BrowserWindow.HTMLTextNameProductName.getText()
String total = BrowserWindow.HTMLTextNameTotalValue.getText()
Total = 10 and Value = 10 since we just bought a single product. Now when we run the testcase, we are sure to get a window not unique error since we have the same values in the particular table. One simple way to bypass this write this simple statement
This makes the unique option set to false.