Issue in capturing the selectors from Chrome Alert Box

Hi,
I am unable to capture the Selectors for the Chrome browser Alert box. Is there any issue or any solution to capture.
I have installed Chrome extension correctly, Also tried reinstalling of the extension.

Have a look at this. It should help.

Thanks,
Rammohan B.

I have tried this topic and samples too, Moreover my application will run only in chrome browser.
Any other suggestion ??