Using GestureLibrary with ScrollView

As I mentioned on title, app has a ScrollView and a GestureDetector too. Outside of ScrollView's touch events, GestureDetector handling swipe actions like left to right and right to left. They're all working well.

Now I want to add a GestureLibrary -I mean raw- to Activity. I've looked different sources and somehow added properly. Simply, layout looking like this:

<android.gesture.GestureOverlayView
    android:id="@+id/gOverlay"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <ScrollView 
        android:id="@+id/content_scroll"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:scrollbars="none">

            </ScrollView>
            <!-- Other views -->
</android.gesture.GestureOverlayView>   

It's drawing as I wanted (the yellow line) but it's not triggering any methods. Here how I implemented OnGesturePerformedListener:

    /*
     * Gestures
     */
    gLibrary = GestureLibraries.fromRawResource(this, R.raw.gestures);
    if (!gLibrary.load()) { finish(); }
    GestureOverlayView gestureOverlayView = (GestureOverlayView) findViewById(R.id.gOverlay);
    gestureOverlayView.addOnGesturePerformedListener(gestureListener);  

And here is gestureListener:

private OnGesturePerformedListener gestureListener = new OnGesturePerformedListener() {
    public void onGesturePerformed(GestureOverlayView overlay, Gesture gesture) {
        ArrayList<Prediction> predictions = gLibrary.recognize(gesture);            
        if (predictions.size() > 1) {
            for(Prediction prediction: predictions){
                Log.d("Test", "Looking for gestures");
            }
        }
    }
};

That's all. By the wall, I tried this source code with in different Activity which