futo-keyboard/java/res/drawable/keyboard_popup_panel_background_lxx_light.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape>
            <solid android:color="@color/emoji_tab_page_indicator_background_lxx_light" />
            <corners android:radius="8dp" />
        </shape>
    </item>
</selector>