This is themable; look at the windowContentOverlay
attribute. In particular, you can create a new theme:
<style name="Theme.Foo" parent="android:style/Theme.Light">
<item name="android:windowContentOverlay">@null</item>
</style>
And then declare that your activity should use this theme:
<activity android:name=".FooActivity"
android:theme="@style/Theme.Foo"> ...
Although a better option is to set this theme for all activities in the application, for consistency:
<application android:theme="@style/Theme.Foo"> ...
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