Apps Issue with combining a View-descendant and LinearLayout

[siberianowl]

I would like to show on screen a custom-drawing object and several 'normal' widgets. So I did a screen layout like this:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="[URL]http://schemas.android.com/apk/res/android[/URL]"
  android:layout_height="fill_parent"
  android:layout_width="fill_parent"
  android:orientation="vertical">
    <myView
        android:layout_width="wrap_content" 
        android:id="@+id/blackboard" 
        android:layout_height="wrap_content" 
        android:layout_margin="2sp" android:clickable="true"></myView>
    <LinearLayout android:layout_width="fill_parent" 
                android:orientation="horizontal"
                android:id="@+id/contorlPanel"
                android:layout_height="fill_parent">
        <TextView android:text="TextView"
                  android:id="@+id/textView1" 
                  android:layout_width="wrap_content" 
                  android:layout_height="wrap_content"/>
    </LinearLayout>
</LinearLayout>

myView class is a direct descendant from a View. Also I want to add in run-time several Button widgets into my R.id.controlPanel.

In onCreate() of my activity I have a code like this:

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.boardScreen);
        myView board = (myView)findViewById(R.id.blackBoard);
        board.setDataSource( ... );
        LinearLayout controlPanel = (LinearLayout)findViewById(R.id.contorlPanel);
        Button btn = new Button(getApplicationContext());
        btn.setText("new button");
        controlPanel.addView(btn);
   }

The problem with the above code is that my custom drawing object takes all space on screen and all objects in controlPanel layout are somewhere below. I do not see nor design-time created TextView, nor run-time created buttons. I do not understand why is it so? I already set
android:layout_height="wrap_content"
for my myView object, why does it takes whole screen?
Any ideas would be appreciated.