Google Widget Extension problem

Hi everyone, I want to use google map widget and I follow this post Display Geolocation Data Using Google Maps Part 1  when I finished Step.1 then in step.2 i create a mashup and want to add google map widget but the google widget did not appear in Widget tab. 

I tried to remove and reinstall the extension but the google widget still not appear. 

Can anyone tell me how to solve it ? Thanks a lot!