Hi Andrei, it sounds like it's probably some feature of the tablet software getting in the way like it's waiting to recognize a gesture or something like that.

See here for some tablet settings that you can adjust which may make a difference:

http://www.polycount.com/forum/showthread.php?t=73758
http://volnapc.com/how-to-get-rid-of-those-annoying-circles-from-your-wacom-cursor-in-windows-7
http://www.designimage.co.uk/how-to-remove-the-annoying-windows-7-circle/

- Michael