Android :: ListView Not Selectable Anymore In Row Layout?

When I use a ImageButton in the ListView row, the ros is no selectable. When I change it to a ImageView it is selectable. I have this simple row layout, and below is my list , am I missing something simple?

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="fill_parent" android:layout_width="fill_parent"
android:orientation="horizontal" android:id="@+id/layoutrowtop">
<ImageButton android:id="@+id/imgDetailDisclosure"
android:layout_height="fill_parent" android:layout_width="48dip"
android:layout_gravity="center_vertical" android:background="#00000000">
</ImageButton>

<RelativeLayout android:layout_width="wrap_content"
android:layout_height="?android:attr/listPreferredItemHeight"
android:padding="6dip"> <TextView android:id="@+id/firstLine"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:ellipsize="marquee" android:textStyle="bold"
android:textSize="18dp" android:singleLine="true"
android:gravity="top" > </TextView>

<TextView android:id="@+id/secondLine" android:layout_height="fill_parent"
android:layout_below="@+id/firstLine" android:layout_width="wrap_content"
android:ellipsize="marquee" android:textStyle="italic"
android:textSize="14dp" android:singleLine="false"
android:gravity="top" android:lines="2"> </TextView>
</RelativeLayout> </LinearLayout>

<LinearLayout android:layout_height="wrap_content" android:orientation="horizontal"
android:layout_width="fill_parent"> <EditText android:id="@+id/search_box"
android:layout_height="wrap_content" android:layout_weight="1"
android:layout_width="fill_parent" android:hint="type to filter" android:inputType="text"/>

<ImageButton android:id="@+id/search_button" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:src="@drawable/icon_mag_glass"/>
</LinearLayout>
<!-- Set height to 0, and let the weight param expand it -->
<!-- Note the use of the default ID! This lets us use a ListActivity still! -->
<ListView android:id="@android:id/list" android:layout_width="fill_parent"
android:layout_height="0dip" android:layout_weight="1" />