Gizmo adding problems

Hello everyone! May I ask you for help? In general, the situation is as follows: based on jme3 my friend from Germany created a program for editing world data for the game Gothic 3. As a separate module, he wrote a utility for viewing game levels and 3D models. Only there is a small problem - he didn’t include the gizmo in it. I tried to get inspired by the original engine jme3, but I couldn’t manage to add it for object manipulation. Looking at the original SceneEditTool class, I did not understand what was needed SceneComposerToolController and its fields and methods toolController. Can you to look into the class NodeViewerApp? I hope you can tell me how to implement a gizmo for this modification jme3.