I run an app in fullscreen mode where fullscreen is defined as a theme in xml for the entire app.

<style name="AskTingTingTheme" parent="android:Theme">
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowFullscreen">true</item>
    <item name="android:windowBackground">@null</item>
</style>

Generally it works ok, but there are some issues in some cases:

1) when I open the search dialog via search button -> Screenshot: http://tinyurl.com/3xzadft

2) when I open spinner widgets that are very long and fill the screen (so that the list is usually scrollable) -> Screenshot: http://tinyurl.com/39q5ya2

The problem is that when I open the search dialog or spinner widget, the system notification bar occurs for a few millisecs and then scrolls off the screen again. Please see the screenshots linked above.

I'm currently on 2.2 with NexusOne, but same thing happened on 2.1update1 (esp. case 2) as well before.