Hi,

   I’ve already drawn some 3D objects inside the GLView. By the data I got from the mouse_move_cb, I want to recognize some move behavior and popup buttons to ask what next step actions the user want to.

  I need to dynamically create and destroy the buttons on top of GLView. But I only know create the buttons and layout in function create_gui(), it seems the UI components are created statically. How to dynamically create and destroy the buttons on top of GLView?