이해가가지않습니다. 스크롤시 컨텐츠가 사라짐

Question

스크롤뷰를 만들어 그안에 비디오뷰를 만들었습니다.

그리고 그 스크롤뷰를 포함하는 레이아웃이있고, 메뉴도 같이 포함되어있습니다.

스크롤뷰를 이옹해 스크롤을하면 메뉴 레이아웃도 사라지는데 왜그런가요?

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/black"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:clickable="false"
        android:orientation="horizontal">

        <LinearLayout
            android:id="@+id/left_menu"
            android:layout_width="@dimen/main_left_menu_width"
            android:layout_height="match_parent"
            android:orientation="vertical"
            android:padding="@dimen/main_left_menu_padding">

            <Button
                android:id="@+id/btn_param"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="PARAMETER" />rtsp://220.90.135.98:1026view

            <Button
                android:id="@+id/btn_live"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="LIVE" />

            <Button
                android:id="@+id/btn_measu"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="MEASUREMENT" />
        </LinearLayout>

        <RelativeLayout
            android:id="@+id/view_layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_below="@+id/left_menu"
            android:clickable="true"
            android:orientation="vertical">

            <ScrollView
                android:id="@+id/scrollV"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:fillViewport="true">

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

                    <HorizontalScrollView
                        android:id="@+id/scrollH"
                        android:layout_width="match_parent"
                        android:layout_height="match_parent"
                        android:fillViewport="true">

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

                            <com.eoc.portable.component.AdoVideoView
                                android:id="@+id/videoView"
                                android:layout_width="wrap_content"
                                android:layout_height="wrap_content" />
                        </LinearLayout>
                    </HorizontalScrollView>
                </LinearLayout>
            </ScrollView>

            <FrameLayout
                android:id="@+id/touch"
                android:layout_width="match_parent"
                android:layout_height="match_parent">

            </FrameLayout>

        </RelativeLayout>

    </LinearLayout>

</RelativeLayout>