When a Cell is in Edit Mode

Shortcut Function
ARROW_LEFT, ARROW_RIGHT Move cursor in the cell content.
SHIFT+ ARROW_LEFT,

SHIFT+ ARROW_RIGHT

Select cell content left/right.
CTRL+ARROW_LEFT,

CTRL+ ARROW_RIGHT

Move cursor left/right to the next space character.
SHIFT+CTRL+ARROW_LEFT,

SHIFT+CTRL+ARROW_RIGHT

Select cell content left/right to next space character.
ARROW_UP, ARROW_DOWN Move cursor one line up or down.
SHIFT+ARROW_UP,

SHIFT+ARROW_DOWN

Expand selection to line above or below.