The Arrow Styles tab of the Line dialog reached by selecting More Options in the Line section of the Properties deck of the Sidebar seems unnecessary since the Line tab allows you to select Arrow Styles for the Start and End of a line separately. If the Arrow Styles tab is kept, -None- should be added to the list of choices. I did find a workaround. If an arrow style is selected in the Arrow Styles tab, I can choose none for both the Start and End areas of the Line tab. This setting evidently overrides the setting in the Arrow Styles tab.
Ordinary lines have "- none -" (should be "[None]") as arrow style under the Line tab. But the arrow tab does not allow to set this non-style. Idea in bug 127348 is to move the arrow style tab out of the dialog, which should solve this problem. Making this report a duplicate, please comment on the other ticket. *** This bug has been marked as a duplicate of bug 127348 ***