The draw buttons: Draw, O, P, L, R and AvP draw temporary outlines and labels on the image. They do not first erase any previous drawings. This is to enable comparison of different outlines. To see clean outlines, for example, use R, then P.
Dragging or zooming the image will erase any drawings. Just redraw by clicking on the appropriate button, or use the P-Off / P-On button.
The color of the perimeter or label is indicated to the right of the Outline and Label buttons. Clicking these buttons allows you to select a new color.
L Draws blob labels at the centroids.
R Redraws image, erasing all graphics such as perimeters.
P-Off / P-On Toggles automatic drawing of blob perimeters. This is h andy when zooming and scrolling.
Num Points Number of pixels (coordinate pairs) around the outline that are averaged together. Larger number of pixels make smoother outlines. See TOOLS / Fractal - Measure / Bdry C Av.