Can not show popup window out of the keyboard view in Android Pie

I am making a Keyboard which shows a popupWindow of languages. In all device, I get perfect popupWindow outside of keyboard but in only Android Pie, I can not show popupWindow outside of the keyboard.

I want to show popup outside of keyboard's candidateView when Bluetooth keyboard is connected.

I am using this code

setClippingEnabled(false);
showAtLocation(anchor, Gravity.NO_GRAVITY, x, y);

Does someone have any idea, what is the issue?

here is demo app - https://github.com/priyankagb/andoidpiepopupwindowdemo

see screenshots,

In Android Pie in which you can see a small line at the bottom which is popupWindow for languages

Left is Below Pie, Right is Pie

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