Arrows displayed over the edge of the line/curve

[grofaty]

Paint.net 4.0.5 on Windows 7.
1. Shapes and draw rectangle on canvas. Then press Enter to finalize rectangle.
2. Line/Curve, press Shift key and hold and draw line from left to right inside rectangle.
3. From Style right mouse selection select Filled Arrow.

Pinta 1.6.0.62 on Windows 7.
1. Rectangle and draw rectangle on canvas. Then press Enter to finalize rectangle.
2. Line/Curve, press Shift key and hold and draw line from left to right inside rectangle.
3. Click on Arrow 2 checkbox and arrow appears. But look at the arrow it gets beyond the rectangle.

Now observe (see attachment) the result. Paint.net works fine, but in Pinta arrow gets drawn outside of the edge of the line. This is specially annoying when I draw a line and then change line to add arrow, like in this case.