...
Operation Toolpad > Geometry Command Button <font color=!> Edge Command Button > Create Edge !edge_cb-1.jpg|width=25,height=22!> Create Edge !create_edge_cb-1.jpg|width=25,height=22" width="25" />
Select vertex 1 by holding down the Shift button and clicking on it. Next, select vertex 2. Click Apply in the Create Straight Edge window.
...