Please describe the problem:
moving the cursor on an image to be edited leaves a trail of small green circles the same size as the brush selected. Putting another window over the image window removes the trail of circles. 
This is with gimp-2.3.14 running under kde-3.5.6 on a ThinkPad R40 laptop which uses an ATI video card chipset. It makes no difference whether I use the 'radeon' or the 'ati' x-11 driver.

Steps to reproduce:
1. Open an image window
2. drag a painting cursor over the window. don't paint.
3. 


Actual results:
There is a trial of green circles behind the cursor

Expected results:
the green circle should be removed after the cursor moves on giving the appearance of a single circle following the cursor.

Does this happen every time?
yes

Other information:
snapshot at:-
http://shell.clug.net.nz:8080/~chris/gimpSnapshot.png