@gaieus said:
Hi Mark (and welcome)
It's a "Style" setting. Go to Window > Styles and in the dialog In model (the little house icon), select the style you are using (by default there's just one style) > Edit tab > Edge settings.
Now when you are here, turn off extensions and endpoints (I generally turn these off as well as profiles).
If you wish, you can save this file as a template (File menu) and from Window (Sketchup on Mac) > Preferences > Templates use your custom template with these (and in fact any other kind of) settings.
Thank you very much Gaieus! I knew there must be someplace to do this.
Regards,
M.