Adobe Dreamweaver CC 2014 v.13 - Manual (Page 217)

Only set properties
To set a property, such as, width or border-collapse, click the required options displayed adjacent to the property in the Properties pane.
For information on setting gradient background or box controls such as margins, padding, and position, see the following links:
Set margins, padding, and position
Apply gradients to background
Use Flexible Box layouts
Overridden properties are indicated using a strikethrough format.
Strikethrough format for overridden properties
Set margins, padding, and position
Using the CSS Designer's Properties pane, you can quickly set the margins, padding, and position properties using the box controls.
'margin' property
210