Testing the popup with Selenium IDE
Getting below error :
Window does not exist. If this looks like a Selenium bug, make sure to read http://seleniumhq.org/docs/02_selenium_ide.html#alerts-popups-and-multiple-windows for potential workarounds.
It's like when I click on the lookup icon a new window opens and when I select some value there and the page redirects of the active page.
This scenario I'm not able to achieve through IDE automation.
you can use Java AWT Robot class to handle the scenario. using this class you can perform mouse actions on basis of screen coordinates or you can use AutoIT to automate this process for handling windows popup which cannot be done by selenium itself because it works only on web elements.