In Lianja it is possible to style UI elements with CSS that have specific attributes.

Code:
*[com_mycompany_mandatory="true"] { border:1px solid red; }
You can use the AddProperty() method (which is a core method on each Lianja UI class) to add a property/attribute. These are case sensitive and I recommend that you use a standard naming convention so as not to interfere with internal properties and those of other third party components.

These can be used very effectively in the Lianja UI state machine.

Almost all UI controls that are composite (made up of other controls such as scrollbars etc) can have each of their UI elements skinned.

More on this later.