For more, see Selection Tools
To activate: Toolbar, View menu / Select
Draw a rectangular window to define an area in which to search or select map features on a particular layer. Any feature on current layer that crosses window, or is contained therein, is selected.
To use:
Activate Select Crossing Window tool.
Draw window on map view: Move pointer to a corner of desired area.
Click and hold while moving pointer to corner diagonal from beginning. Release.
Selected features become highlighted.