GUI Additions to VisualizerWithVertexSelection

[sankarip]

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 main branch).

My Question

I'm trying to make an application that lets users select parts of a 3D model and designate them as having certain traits. I want a user to select the points of interest and then click a button that designates them as having a given trait. I would prefer to do this without making the user close the visualization window. I've been trying to use open3d.visualization.VisualizerWithVertexSelection for this, but I can't get it to integrate with tkinter and it doesn't seem to have the capability for adding GUI buttons to the visualization window. Is there some other solution I should try for this?