If you have a wheel mouse, try this next time you have the Object Alignment menu open (Arrange > Align).
Click the first option in either the Horizontal or Vertical Positions drop down list. The list will drop down. Click again on the first entry which now becomes selected. Roll the mouse wheel one way and the other. The icons in the preview window will move into the positions of the align options.
More Wheel Mouse Tips:
Thanks to Dennis Cox for reminding me about these wheel mouse goodies:
Roll the wheel to scroll the page up and down.
Hold down SHIFT to scroll left or right.
Hold the wheel down to slide the page around in the window.
Click the wheel to center the view around the mouse pointer
CTRL-click to zoom in SHIFT – click to zoom out
Hold down CTRL for variable zoom in (scroll the wheel up) or zoom out (wheel down).
(Courtesy of Xara’s Help menu)