I use it constantly and now see it is gone in 4 beta. I found this thread by searching for "freeform shape tool missing paint.net 4". I use when doing just that, drawing freeform shapes esp. when I am drawing over things that need to be erased/corrected. Also the lasso tool/fill does reproduce it exactly because the freeforrm shape allows point-line-point drawing by clicking and the lasso does NOT do that... Also I see Escape doesn't deselect anymore, that is a shame as well.