Upgrading app to 2.1.0b2 via sencha tools forgets app.css
I've originally created my ST 2.0 app via the sencha tools.
Now when I upgraded to 2.1.0b2 via the same sencha tools via 'sencha app upgrade etc.' my app no longer displayed anything, while I could see that all data was loaded. It only showed a grey screen.
As it turned out, this is caused by the upgrade process that didn't upgrade the app.css in the resources folder.
I don't know if this should be considered a bug, as some people may modify the app.css to their needs, but I think that at least some kind of warning should be displayed.