Google Maps v2 lag after popping their fragment back from stack

Question

I have an Activity with a MapFragment that I add to the Activity programmatically using a FragmentTransaction:

Answer 1

I have fixed it by dismissing the ProgressDialog already at the end of the AsyncTask's doInBackground() method rather than at the beginning of the onPostExecute() method.

Which is a bit weird because I actually thought I shouldn't touch things from the UI in the doInBackground() method... If someone wants to elaborate on it a bit, I would be glad to learn why it works like this.