"Apple Dock is the command center for your Mac.

With Apple Dock you can run applications, switch between apps, open documents and links.

Unfortunately, Apple Dock lacks many useful features such as managing windows and switching between windows, appearance customizations, hiding app icons.

Solution?

ActiveDock is a full replacement for Apple Dock with many new features.

ActiveDock allows grouping of documents and apps, quicker switching between apps and windows, managing windows right from Window Previews panel.

Also you can customize the appearance of icons and the dock itself as you need."

- MacPlus Software