Calling .strokeWidth(0) on a circle has the same effect as calling .strokeWidth(1). To reproduce an example of the bug, enter the following code in the jcotton tutorial page:
tutorialCanvas.add(jcotton.circle(37,40,20).strokeWidth(0));
tutorialCanvas.add(jcotton.circle(81,40,20).strokeWidth(1));
tutorialCanvas.add(jcotton.circle(125,40,20).strokeWidth(2));
tutorialCanvas.add(jcotton.circle(169,40,20).strokeWidth(3));
tutorialCanvas.add(jcotton.rect(17,80,40,40).strokeWidth(0));
tutorialCanvas.add(jcotton.rect(61,80,40,40).strokeWidth(1));
tutorialCanvas.add(jcotton.rect(105,80,40,40).strokeWidth(2));
tutorialCanvas.add(jcotton.rect(149,80,40,40).strokeWidth(3));
The leftmost circle should not be visible, but it is. Compare with the leftmost square, which is invisible.
This bug is specific to Chome/Chromium.