If you switch out of the app, put the device to sleep, or probably a range of other things while the Initializing popup is displayed it will never go away. The only way to stop it is to Force Stop the application. I assume it's waiting for the aborted HTTP response. Back button or something should work to close it.
To reproduce:
- Start the app
- As soon as it shows the HomeActivity and starts Initializing, press the device power button.
- Press the device power button again.
- The popup will never go away.