Why does a circle form at the point of contact

I hold the stylus as an ordinary pencil without pressing ctrl-key or the buttons on the Bamboo stylus.  After I select the pencil, adjust the size, opacity, flow and screen mode I try to draw or trace over an image. Immediately the size window opens. and when I attempt to draw the white circle appears at the pen tip. I do not see the same window as in your image; mine does not show the angle. Nor is there a menu showing feather, smooth etc.

Now here's something new: I have been in Painting format but when I changed to Essentials the circle does not appear neither does the size window open. I can open the size window by clicking to the right of the brush picker. Very weird.Because now I have changed back to Painting and the pen behaves normally without the circle and size window.  This is the most recently updated Photoshop as of a few days ago.

Yes Thanks. It seems to be working OK now. A mystery that may crop up again. However,  I could have taken a screen shot but I do not see how to attach it to my reply.