You can get GeoGebra to let points to capture the grid points, so it's suffered nemmere that construct shapes.

1. Go to Settings.
2. Press 'Catch point'.
3. Choose, what GeoGebra to Gore.
4. Try thee suffered from between Automatic, Catch the net, Lock to lattice and From.
5. Try the low polygon after every time you lichens on the, whether GeoGebra should capture points to the grid.