The control alignment section will not be available unless multiple controls are selected. Holding the Shift or Ctrl key while clicking on controls allows multi-selection.
Left: Aligns the left border of the selected controls.
Right: Aligns the right border of the selected controls.
Center: Aligns the center of the selected controls vertically.
Top: Aligns the top border of the selected controls.
Bottom: Aligns the bottom border of the selected controls.
Middle: Aligns the center of the selected controls horizontally.