1. Setup
XAMPP
Sencha 1.1.0
Sencha twitter example

2. Steps to reproduce
1. go to twitter example on your phone via Safari
2. add an icon to the home screen
3. then exit the Safari
4. restart Sencha twitter from the home screen icon.
5. if you use a proxy you will see that there are 2 calls to the phoneStartupScreen image
With XAMPP, i used to print the logs out:
tail -f access_log | grep phone_startup.png

The point is why the phoneStartupScreen got called twice as it was already downloaded when creating the icon on the home screen. To test this, at step 3, turn off the wifi and restart Sencha twitter from the home screen, you will see a splash image is there before the error message pops up.