With Enterface, you can quickly create a page full of elements that fit and flow together, rather than manually positioning each object. For example, you can take a bunch of form fields and stack them automatically by creating a vertical group. Then you can easily change the margin between each form field.
Here's another example. You have a container element, and two sub-containers. The sub-containers are inside the container, and the container has padding of 10 pixels, so the sub-containers are automatically inset 10 pixels. You can make the height of these sub-containers to be 100% of the space available inside the container, so when you change the height of the container, the sub-containers change height too. The width of the left container is set at 200 pixels and the right container is set to 100% of the remaining space. If you want to check out what the layout would look like without the left container, you can just collapse it, and see the results. The right sub-container fills in the newly vacated space.