removes focus moving, see #756

Author: hneemann

src/main/java/de/neemann/digital/gui/components/graphics/MoveFocusTo.java

@@ -18,7 +18,7 @@
  * As soon as there are menus, buttons or similar, this listener should
  * no longer be used.
  */
-public class MoveFocusTo implements WindowFocusListener {
+public final class MoveFocusTo implements WindowFocusListener {
 
     /**
      * Adds the listener to the given child dialog and moves the focus to the given parent