I experienced that strange behaviour several times recently, so not sure which version of Rhino 7 introduced it. Double-clicking on a control point polygon edge usually selects the entire row of control points. However, I noticed that in rare occasions, depending on the camera orientation around the object, a double-click will result into selecting only two control points (basically it will acts as a single-click instead). I use Logitech G502 mouse that has a dedicated button for double-click, yet even it can’t select the entire row at certain positions of the camera relative to the object. This is a bit annoying, because the user expects that the entire row of control points will be selected, thus he or she could be mislead about the actual number of selected points.
The video was captured and uploaded on 27th of December 2021 with the following version of Rhino 7 that I still use to date, but I forgot to report the bug earlier:
Version 7 SR14
(7.14.21348.13001, 2021-12-14)
Commercial