Snap Grid

Dialog Box-Builder Preferences Snap Grid
Allows you to restrict the possible positions and sizes of your interface objects, similar to the Working grid in the modeling window.
When you drag an item with the mouse to move or resize it, the mouse position will snap to the nearest grid point. Because the snap grid points are not visible, and the default grid is very fine (2 pixel distance) it is generally not very noticeable.
You can turn this option on or off in the Option menu in the Dialog-Box Builder.
 
For the option:
Do the following:
Horizontal Grid Spacing
Enter a value to set the horizontal distance between grid points.
Vertical Grid Spacing
Enter a value to set the vertical distance between grid points.
Horizontal Grid Offset/
Vertical Grid Offset
Enter the number of pixels from the top left border to begin grip snaps.