Picking mode allows you to select and move objects, such as points, curves, and planes.
To enter picking mode, click Select
            
 . To leave picking mode (that is, switch back to viewing
                mode), click Rotate
            
  or Pan
            
 .
To temporarily enter picking mode when you are in viewing mode, hold Ctrl+Shift. When you release the Ctrl+Shift keys, you will return to viewing mode.
When you click Select
            
  to enter picking mode, a toolbar icon appears to enable you to
            change the selection method:

For details, see Viewer Toolbar.