Android : Button not working(No color change)

I just create a new project with blank activity and then drag and drop a Button. When i run it on a 2.3.6 samsung i9000 the button has the same background both when pressed or unpressed.

<RelativeLayout 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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

<TextView android:text="@string/hello_world"  
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/textView" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="New Button"
    android:id="@+id/button"
    android:layout_centerVertical="true"
    android:layout_toRightOf="@+id/textView"
    android:layout_toEndOf="@+id/textView"
    android:layout_marginLeft="39dp"
    android:layout_marginStart="39dp" />

http://i.stack.imgur.com/ARjSD.png