The size section will not be available unless multiple controls are selected. Holding the Shift or Ctrl key while clicking on controls allows multi-selection.
To Grid: Moves the control(s) to touch the nearest gridline above it.
To Tallest: Changes the size of all selected controls to match the tallest selected field.
To Shortest: Changes the size of all selected controls to match the shortest selected field.
Size to Grid: Changes the size of the selected control(s) to touch the top nearest gridlines above and below it.
To Widest: Changes the size of all selected controls to match the widest selected field.
To Narrowest: Changes the size of all selected controls to match the narrowest selected field.