Two LinearLayouts with same background colour appear different in the parent view
<p>I have this layout:    </p>

<pre><code>&lt;FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
             android:background="@android:color/black"
             android:gravity="center_horizontal"
             android:layout_width="fill_parent"
             android:layout_height="fill_parent"&gt;

    &lt;com.digitaliridium.tides.NVLibrary.NVGlobeView
            android:id="@+id/globeView"
            android:src="@drawable/icon"
            android:background="@color/nvglobebackground"
            android:scaleType="matrix"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/&gt;

    &lt;LinearLayout
            android:background="@color/paneltransparenciesbackground"
            android:orientation="vertical"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"&gt;

        &lt;TextView
                android:id="@+id/globeViewPortName"
                android:textSize="22dp"
                android:textStyle="bold"
                android:background="@android:color/transparent"
                android:layout_marginTop="5dp"
                android:layout_marginLeft="5dp"
                android:layout_width="fill_parent"
                android:layout_height="26dp"/&gt;

        &lt;TextView
                android:id="@+id/globeViewLocation"
                android:textSize="12dp"
                android:layout_marginTop="3dp"
                android:layout_marginLeft="5dp"
                android:background="@android:color/transparent"
                android:layout_width="fill_parent"
                android:layout_height="18dp"/&gt;

        &lt;TextView
                android:id="@+id/globeViewPortType"
                android:textSize="12dp"
                android:background="@android:color/transparent"
                android:layout_marginLeft="5dp"
                android:layout_width="fill_parent"
                android:layout_height="18dp"/&gt;

    &lt;/LinearLayout&gt;

    &lt;LinearLayout
            android:background="@color/paneltransparenciesbackground"
            android:orientation="vertical"
            android:layout_gravity="bottom"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"&gt;

        &lt;RelativeLayout
                android:background="@color/paneltransparenciesbackground"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"&gt;

            &lt;ImageButton
                    android:id="@+id/indicatorMode"
                    android:src="@drawable/nv_selector"
                    android:background="@android:color/transparent"
                    android:layout_marginLeft="10dp"
                    android:layout_width="50dp"
                    android:layout_height="50dp"/&gt;

            &lt;ImageButton
                    android:id="@+id/homePort"
                    android:src="@drawable/nv_home_port"
                    android:background="@android:color/transparent"
                    android:layout_toRightOf="@id/indicatorMode"
                    android:layout_marginLeft="20dp"
                    android:layout_width="50dp"
                    android:layout_height="50dp"/&gt;

            &lt;ImageButton
                    android:id="@+id/gps"
                    android:src="@drawable/nv_gpsarrow_white"
                    android:background="@android:color/transparent"
                    android:layout_centerInParent="true"
                    android:layout_width="50dp"
                    android:layout_height="50dp"/&gt;

        &lt;/RelativeLayout&gt;


        &lt;RelativeLayout
                android:background="@color/paneltransparenciesbackground"
                android:orientation="horizontal"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"&gt;

            &lt;TextView
                    android:id="@+id/viewPointLocation"
                    android:textSize="12dp"
                    android:background="@android:color/transparent"
                    android:gravity="center_vertical"
                    android:layout_marginLeft="5dp"
                    android:layout_width="wrap_content"
                    android:layout_height="30dp"/&gt;

            &lt;TextView
                    android:id="@+id/scale"
                    android:textSize="12dp"
                    android:layout_marginLeft="20dp"
                    android:gravity="center_vertical"
                    android:layout_toRightOf="@id/viewPointLocation"
                    android:background="@android:color/transparent"
                    android:layout_width="wrap_content"
                    android:layout_height="30dp"/&gt;

            &lt;TextView
                    android:id="@+id/distance"
                    android:textSize="12dp"
                    android:layout_marginRight="10dp"
                    android:layout_alignParentRight="true"
                    android:gravity="center_vertical"
                    android:background="@android:color/transparent"
                    android:layout_width="wrap_content"
                    android:layout_height="30dp"/&gt;

        &lt;/RelativeLayout&gt;

    &lt;/LinearLayout&gt;

    &lt;ImageButton
            android:id="@+id/flipView"
            android:layout_marginTop="300dp"
            android:layout_gravity="bottom"
            android:layout_marginBottom="100dp"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:scaleType="center"
            android:src="@drawable/sc_flip"
            /&gt;


&lt;/FrameLayout&gt;
</code></pre>

<p>Here's a shot of the resulting screen</p>

<p><img src="http://i.stack.imgur.com/A1yOR.png" alt="Here's a shot of the resulting screen"></p>

<p>You can see that the semi-transparent panels (the LinearLayouts) appear to have different levels of opaqueness, even though they have the same background colour.</p>

<p>The difference is much more marked on the device screen than it is in the screen cap.</p>

<p>Can anyone spot why?</p>
