Selecting Point of a point cloud using SceneWidget

[OttoDo]

Checklist

• I have searched for similar issues.
• For Python issues, I have tested with the latest development wheel.
• I have checked the release documentation and the latest documentation (for master branch).

My Question

i am using SceneWidget and open3dScene to display my Pointcloud, i would like to be able to click on a point that is displayed and get its coordinates, any ideas? I would like to build sth like the Selection function implemented in open3d.visualization.draw.

[ajktym94]

An example is shown in : https://github.com/isl-org/Open3D/blob/master/examples/python/visualization/mouse_and_point_coord.py