About Arranging Controls on Dialog Boxes
The Dialog editor provides layout tools that align and size controls automatically. For most tasks, you can use the Dialog toolbar. All commands are also available on the Layout menu, and most have shortcut keys.
Many layout commands are available only when more than one control is selected. For information on selecting more than one control, see Selecting Controls.
The location, height, and width of the current control is displayed in the lower-right corner of the status bar. When more than one control is selected, the position indicators show the position of the dominant control (the control with solid sizing handles). The dominant control determines the anchor point for lining up other controls. You can change which control is dominant. For more information, see Selecting Controls.
When the entire dialog box is selected, the status bar displays the position of the dialog box and its height and width.
The location and size of a dialog box, as well as the location and size of controls within it, are measured in dialog units (DLUs). A DLU is based on the size of the dialog box font, normally 8-point MS Sans Serif. A horizontal DLU is the average width of the dialog box divided by four. A vertical DLU is the average height of the font divided by eight.