Needle up behaves similar to trim command. It allows user to draw objects and avoid their connection with stitch. While trim command cuts the thread and skips to next one, needle up does not cut the thread at all.
Selecting needle up immediately changes mouse cursor icon to needle
Confirming the change, user can draw the second object. Its starting point is the place where needle up option was confirmed.
If needle up is used, during embroidery process, embroidery machine does not put stitches, just one long stitch.