Use the last icon in the toolbox. The icon is divided into two sections. The part on the right is represented by up and down arrows. If you click to the left, a pop-up menu appears which contains different line styles. Choose None from the bottom of this menu.
KaleidaGraph is a thoughtfully designed graphing and data analysis application for research scientists, as well as for those in business and engineering fields. It produces publication-quality graphs, and easily converts the most complex data into a functional display.