A Soft Group is similar to a Group but with several key differences.
A Soft Group can contain items across one or even several layers. Selecting an item on one layer will automatically select the corresponding soft grouped items on the other layers.
Soft Groups support synchronized text. The text will be synchronized for editing for two or more objects with the same text within a Soft Group.
Please view the Designs Gallery, you will find the majority of the buttons are soft grouped. This allows you to move or even resize a button on the MouseOff layer and the same alterations to be automatically made to the button on the MouseOver layer. Likewise, you can edit the text for the button on one of the layers and the changes made to the text will be synchronized on the other layer.