res/layout/filtershow_state_panel_new.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:custom="http://schemas.android.com/apk/res/com.android.gallery3d"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:background="@color/background_main_toolbar">

    <View
            android:background="@color/toolbar_separation_line"
            android:layout_height="1dip"
            android:layout_width="match_parent"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

    <HorizontalScrollView
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:scrollbars="none">

        <com.android.gallery3d.filtershow.state.StatePanelTrack
                android:id="@+id/listStates"
                android:orientation="horizontal"
                android:layout_width="match_parent"
                android:layout_height="48dip"
                custom:elemEndSize="128dip"
                custom:elemSize="128dip"
                android:layout_margin="0dip"
                android:animateLayoutChanges="true" />

    </HorizontalScrollView>

    <ImageButton
            android:id="@+id/toggleVersionsPanel"
            android:layout_width="wrap_content"
            android:layout_height="48dip"
            android:src="@drawable/filtershow_versions_compare"
            style="?android:attr/borderlessButtonStyle"
            android:layout_gravity="center"/>

    </LinearLayout>

    <View
            android:background="@color/toolbar_separation_line"
            android:layout_height="1dip"
            android:layout_width="match_parent"/>

</LinearLayout>