Seeing black area in system ui

[wonderdragons]

AndroidFullScreen.stage = stage;
AndroidFullScreen.immersiveMode();
stage.setOrientation(StageOrientation.UPSIDE_DOWN);
stage.setOrientation(StageOrientation.UPSIDE_DOWN);

Tried leanmode, immersiveMode(true), fullscreen() everything...but still black on system ui.
If I use showUnderSystemUI(), it shows system ui on top and if I use showUnderSystemUI(), app goes behind systemui on top. But I want to remove system ui completely and app take that place. You have any sample for it?

In my xml, I am using <meta-data android:name="android.max_aspect" android:value="2.16" /> by the way.

Thanks