import eu.svjatoslav.sixth.e3d.geometry.Point3D;
 import eu.svjatoslav.sixth.e3d.gui.ViewFrame;
 import eu.svjatoslav.sixth.e3d.gui.ViewPanel;
-import eu.svjatoslav.sixth.e3d.gui.humaninput.WorldNavigationTracker;
+import eu.svjatoslav.sixth.e3d.gui.humaninput.WorldNavigationUserInputTracker;
 import eu.svjatoslav.sixth.e3d.math.Transform;
 import eu.svjatoslav.sixth.e3d.renderer.octree.OctreeVolume;
 import eu.svjatoslav.sixth.e3d.renderer.octree.raytracer.Camera;
 import java.awt.event.KeyEvent;
 import java.util.Vector;
 
-public class OctreeDemo extends WorldNavigationTracker {
+public class OctreeDemo extends WorldNavigationUserInputTracker {
 
     private static final double magnification = 5;
     private final LineAppearance gridAppearance = new LineAppearance(40, new Color(255,
                 Color.WHITE, Color.PURPLE);
         shapeCollection.addShape(message);
 
-        viewPanel.getKeyboardFocusTracker().setFocusOwner(this);
+        viewPanel.getKeyboardFocusStack().pushFocusOwner(this);
         viewPanel.repaintDuringNextViewUpdate();
     }
 
 
 import eu.svjatoslav.sixth.e3d.gui.Avatar;
 import eu.svjatoslav.sixth.e3d.gui.ViewFrame;
 import eu.svjatoslav.sixth.e3d.gui.ViewPanel;
-import eu.svjatoslav.sixth.e3d.gui.humaninput.WorldNavigationTracker;
+import eu.svjatoslav.sixth.e3d.gui.humaninput.WorldNavigationUserInputTracker;
 import eu.svjatoslav.sixth.e3d.math.Transform;
 import eu.svjatoslav.sixth.e3d.renderer.raster.Color;
 import eu.svjatoslav.sixth.e3d.renderer.raster.ShapeCollection;
 import java.awt.event.KeyEvent;
 
 
-public class Main extends WorldNavigationTracker {
+public class Main extends WorldNavigationUserInputTracker {
 
     private static final Matrix MATRIX = new Matrix(
             new Point3D() // position matrix in the center of the scene
         setAvatarOrientation(viewPanel.getAvatar());
 
         // enable receiving of keyboard events
-        viewPanel.getKeyboardFocusTracker().setFocusOwner(this);
+        viewPanel.getKeyboardFocusStack().pushFocusOwner(this);
 
         // Done! World is built. So ensure screen is updated too.
         viewPanel.repaintDuringNextViewUpdate();