If the Show Area and Line Vertices option is
enabled (Shift+V is the keyboard shortcut to toggle this setting), you
can also select individual vertices on area and line features. You must
select vertices before accessing the Digitizer
right-click menu options.
With vertices selected, the Digitizer sub-menu will appear, with options (below) that allow you to work with individual vertices in area and line features appear in the right-click options menu. Selected vertices will be shown on the display with a circle around them.
To select vertices, simply left click near a vertex to select the closest, or drag a box to select all vertices within the box. The same behavior modifications occur as described above if the CTRL and/or SHIFT keys are pressed when selecting.
Hold down the 'S' key when left clicking, to only consider vertices from already selected lines or areas.