Thanks Larry,
This happens to me no matter what files I am in. large or small, complicated or simple. I have tried using all methods, click-drag, right click select all, dragging line through etc. When I select individually and add to selection using ctrl then all is fine.
Also, when i select, the elements appear to select instantly, ie, all change to highlighted selection colour, it is at that point that the spinning circle appears.
File attached for testing is medium complexity.
(Please visit the site to view this file)