Android Button orders to front automatically

something weird is happening to me. I have this layout:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

<Button
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/gray_dark" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:drawableTop="@drawable/some_drawable"
    android:text="Some text" />
</RelativeLayout>

And I would expect that TextView is visible above button. But for some reason the Button goes to front automaticaly, covering up the textview. When I change Button to common View, the order is right.

Is there something I am missing about Buttons in Android? Thanks

Edit:

Preview:

I just tried the same thing and the weird thing is, it also happend to me. I fixed it like this

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true">

        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="#FF0000"
            android:text="lalala"/>

    </LinearLayout>

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:background="#FFFF00"
        android:text="lalala"/>

</RelativeLayout>