Extending and Reducing the Selection Using the Arrow Keys

To move the start or end of a selection in the wave window to the left or right, hold down Shift and press the Left Arrow/Right Arrow. To move it in bigger steps, press Page Up or Page Down.

To extend a selection to the previous or next boundary in the wave window (marker or start/end of the audio file), hold down Ctrl/Cmd-Shift and press the Left Arrow or Right Arrow.