Fix #7435 Canvas in gui_ex.py tutorial does not scale with window size
Fix #7435 Canvas in gui_ex.py tutorial does not scale with window size

olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root