0 to -750 ( twips )
-15 (15 twips)
Determines the current setting for the width of the borders around all the windows with borders that can be sized.
To change the value of this entry, double-click Display in Control Panel, and then click the Appearance tab. Select Active Window Border from the Item list, and then set the value of Size. The numbers in the Size box correspond to pixels, where one pixel equals fifteen twips.
Changes made in Control Panel are effective immediately. Changes made in the registry are not effective until you log off and then log on again.
Values entered in twips (minus values) are rounded to the nearest pixel value. For instance, -17 converts to 1 pixel, and -28 converts to 2 pixels.
The registry also accepts values in pixels (0 to 50); however, any values entered in Control Panel will be converted to twips in the registry.