When you have a Sencha Touch App in fullscreen mode, the URL bar is hidden. But sometimes on Android it does show up, which breaks the layout of the App if you have a docked item on the bottom of your App. On iOS this problem does not occur. The URL Bar shows up for example if you click into a text element within a form.
I get exactly the same issue. I've used fullscreen: true but this seems to only work intermittently.
It's odd though, because sometimes it does work as expected. I've got a form with 3 fields and sometimes the view is correctly rendered full screen, even when I click in a field the URL bar doesn't appear.
Then I'll refresh the browser to reload the application and it'll then revert back to having the URL bar at the top.
There doesn't seem to be any consistency on Android.