In previous versions of Liferay DXP, administrators could display or hide the application borders through the Show Borders option of the look and feel configuration menu. In Liferay DXP 7.0 this option has been replaced with Portlet Decorators, a more powerful mechanism to customize the style of the application wrapper.
If you inspect the markup of your Liferay application when it’s on a page you’ll observe that it is wrapped by two layers. Among other things, these layers provide some common basic features like the drag and drop and the application border style. In order to protect these features, you can’t modify the markup of these layers directly with a theme.
Portlet Decorators provide a mechanism to add a CSS class to one of these wrapping layers via a user’s setting. By defining styles for this class in your theme, you can change the look and feel of the application instances where the Portlet Decorator is applied, including its wrapper.
The figure below shows the markup of the layers wrapping a Liferay application when the Decorate Portlet Decorator is applied:
Once your Portlet Decorator is complete, apply it to your applications through the Look and Feel Configuration menu.
Your portlet’s decor is now in your hands.