It select vertices, lines and faces on the view. Several method for selection can be switched.
It selects a vertex, line or face normally.
You can select or deselect continually with dragging of left button. (Cannot select a line.)
All joined faces with clicked vertex or face are selected or unselected. (Cannot select a line.)
Click a line, and it selects or unselects belted vertices and faces.
(Cannot select a line.)
It continuously selects lines joined to the clicked or dragged line. When the line has been clicked, lines from the clicked to the farthest are selected together. When the line has been dragged, it selects while gradually spread.
It selects vertices/faces while gradually spread by dragging.
The vertices/faces on the shortest path through the beginning and the end point of dragging are selected.
The object that contains the clicked vertex, line, or face is made current.
The vertices traced by dragging are selected.