I have simple activity with button. If I press this button then I show dialog with fixed panel on bottom and scrollable content above. Here is how it looks:

android.app.Dialog d = new android.app.Dialog(this);
d.setContentView(R.layout.dialog);

d.findViewById(R.id.confirm).setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        showMsg();
    }
});


d.show();

However, I need full screen activity. I defined my own theme and applied it in AndroidManifest.xml

<activity android:name=".MainActivity"
    android:exported="true"
    android:resizeableActivity="true"
    android:theme="@style/Theme.NoBackground">

Thema definition:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="Theme.NoBackground" parent="android:Theme.NoTitleBar.Fullscreen">
        <item name="android:windowBackground">@null</item>
        <!--<item name="android:windowSwipeToDismiss">false</item>-->
    </style>
</resources>

After that is the dialog's layout broken and I see this:

There appears empty space on top of dialog. This I fixed after inheriting from Dialog and fixing constructor this way:

public class MyDialog extends Dialog {
    public MyDialog(Context context)
    {
        super(context);

        requestWindowFeature(Window.FEATURE_NO_TITLE);

        if (Build.VERSION.SDK_INT < 18) {
            return;
        }

        getWindow().setFlags(
                WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
    }

}

However, bottom bar is still missing. Is invisible. It exists and is placed correctly, but is invisible. If I tap on the place where should be button "OK" then I see correctly Toast message.

I must say, inherited MyDialog with full screen activity correctly works up to android 12. It is broken since android 12. Can someone help me to fix it?

Here is how looks the layout for dialog:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minWidth="270dp"
    android:orientation="vertical" >
    <ScrollView
        android:id="@+id/button_menu_mainscrollview"
        android:layout_width="match_parent"
        android:layout_height="0dip"
        android:layout_weight="1" >
        <LinearLayout
            android:id="@+id/button_menu_mainview"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            android:paddingBottom="5dp" >

            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button1" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button2" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button3" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button4" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button5" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button6" />

            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button7" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button8" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button9" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button10" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button11" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button12" />

            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button13" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button14" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button15" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button16" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button17" />
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Button18" />
        </LinearLayout>
    </ScrollView>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="5dp" >

        <Button
            android:id="@+id/confirm"
            android:layout_width="80dp"
            android:layout_height="35dp"
            android:layout_centerHorizontal="true"
            android:scaleType="centerInside"
            android:text="OK"/>

    </RelativeLayout>

</LinearLayout>

I attached link to simple example for android studio - here.