Q:

Is this a real bug?

I don't know why, but my layout color just stops in the bottom of the screen.
I don't think my code is doing that.
And, by the way, does anyone know where to get ideas from a simple layout like this? TextViews and EditTexts?  
Mine looks awful

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
  android:background="@color/AMOB_gray" 
tools:context="com.example.tiagosilva.amob_android.TubeDataFragment" >

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="20dp"
    android:gravity="center"
    android:background="@color/AMOB_gray">

<TextView
    android:id="@+id/textView13"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:text="@string/material"
    android:textColor="@color/AMOB_yellow"
    android:textSize="25dp" />

<Spinner
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/snipperMaterial">
</Spinner>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/diameter"
    android:textColor="@color/AMOB_yellow"
    android:textSize="25dp" />

<EditText
    android:id="@+id/et_diameter"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/round"
    android:ems="10"
    android:inputType="number"
    android:padding="10dp"
    android:text="0"/>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/thickness"
    android:textColor="@color/AMOB_yellow"
    android:textSize="25dp"
    android:gravity="center"/>

<EditText
    android:id="@+id/et_thickness"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/round"
    android:ems="10"
    android:inputType="number"
    android:padding="10dp"
    android:text="0"/>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/clr"
    android:textColor="@color/AMOB_yellow"
    android:textSize="25dp"
    android:gravity="center"/>

<EditText
    android:id="@+id/et_clr"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/round"
    android:ems="10"
    android:inputType="number"
    android:padding="10dp"
    android:text="0"/>

<Button
    android:id="@+id/btn_save_tube"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/round_buttons"
    android:text="@string/save"
    android:textColor="@color/AMOB_gray"
    android:layout_marginTop="10dp"/>

</LinearLayout>

</ScrollView>

A:

Instead of this:
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.tiagosilva.amob_android.TubeDataFragment" >

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="20dp"
    android:gravity="center"
    android:background="@color/AMOB_gray">

Try this 
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.tiagosilva.amob_android.TubeDataFragment" 
android:background="@color/AMOB_gray">

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="20dp"
    android:gravity="center">

So to move the background color inside the root ViewGroup

