title: android: fill_parent of child view fills screen
body: <p>I'm trying to replicate a spinner control (please don't ask why) I'm struggling with the divider. The fake spinner looks fine until I add the divider to the left of the imageview. Once I add the divider it's height fills the remaining portion of the screen. Can someone please explain this?</p>
  
  <p>The following xml:</p>
  
  <p>.......</p>
  
  <pre><code>        &lt;Spinner 
              android:id="@+id/equipment_spinner"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"/&gt;
          &lt;RelativeLayout
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"&gt;
              &lt;Button
                  android:layout_width="fill_parent"
                  android:layout_height="wrap_content"
                  android:layout_alignParentRight="true"/&gt;
              &lt;ImageView
                  android:id="@+id/spinner_arrow"
                  android:layout_width="45sp"
                  android:layout_height="wrap_content"
                  android:layout_alignParentRight="true"
                  android:layout_centerVertical="true"
                  android:src="@drawable/spinner_arrow"/&gt;
          &lt;/RelativeLayout&gt;
      &lt;/LinearLayout&gt;    
  &lt;/ScrollView&gt;
  </code></pre>
  
  <p></p>
  
  <p>produces the following screen:</p>
  
  <p><img src="https://i.stack.imgur.com/5ectx.png" alt="enter image description here"></p>
  
  <p>once I add the divider, the xml looks like this:</p>
  
  <pre><code>        &lt;Spinner 
              android:id="@+id/equipment_spinner"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"/&gt;
          &lt;RelativeLayout
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"&gt;
              &lt;Button
                  android:layout_width="fill_parent"
                  android:layout_height="wrap_content"
                  android:layout_alignParentRight="true"/&gt;
              &lt;ImageView
                  android:id="@+id/spinner_arrow"
                  android:layout_width="45sp"
                  android:layout_height="wrap_content"
                  android:layout_alignParentRight="true"
                  android:layout_centerVertical="true"
                  android:src="@drawable/spinner_arrow"/&gt;
              &lt;View
                  android:background="#e7ebe7"
                  android:layout_width="1dip"
                  android:layout_height="fill_parent"
                  android:layout_toLeftOf="@id/spinner_arrow"/&gt;
          &lt;/RelativeLayout&gt;
      &lt;/LinearLayout&gt;    
  &lt;/ScrollView&gt;
  </code></pre>
  
  <p></p>
  
  <p>which produces the following screen:</p>
  
  <p><img src="https://i.stack.imgur.com/BHIjR.png" alt="enter image description here">
  <img src="https://i.stack.imgur.com/J56Kj.png" alt="enter image description here">
  can anyone spot what i'm doing wrong here?...</p>