When selecting the grid points it disappears (it is not visible, for example, by dragging it with the gumball). It happens in shaded mode.
Usually, when you select an object, this is highlighted yellow and nothing disappears from the view (in the shaded mode view). It’s a bug…
Thanks. Reported: https://mcneel.myjetbrains.com/youtrack/issue/RH-41159.
Pointclouds in Rhino 6