This is an easy one, but it makes using Actions a lot easier. It's called Button mode, and it hides all of the Commands and tools for editing Actions. This makes it look like a panel full of nice, pretty buttons just waiting for you to push them.
To activate it, simply choose Button mode from the Actions palette's side menu. The Actions appear as buttons in the colors you gave them when you created them (see Figure 4).
Plus, when you stop an Action, its button turns red, so you can just click it to restart it. This is helpful when you use a stop to hold an Action so that the user can apply a manual edit in the middle of an Action.
Object Oriented Programming is the realm of, well, programmers. It's kind of a way of breaking a program down into smaller modules that are independent of one another, yet able to work together. The advantage of this approach is simple. If you need to fix a module, you can fix it in one place, and it's updated wherever it gets used. (Now then, for you REAL programmers out there, I have simplified things, and I know it. Don't bother to send me email telling me so.)
Actions can act this way, too. While recording an Action, just play an existing one. It will then be added to the recording as a Command. It doesn't add the Commands from the one you played. It adds it as an object, which means that you can change the Action and it will update within any Action that refers to it.
A caveat: Don't toss Actions that you refer to. If you do, the Actions referring to them will fail. If you plan to use Actions this way, I suggest a set to hold the modules you intend to use.
Figure 7 The Photo Oldmaker Action in this figure includes a Play Action Command. It refers to the Action, Downsample and Save As.