The other parameter, WindowMode, lets you specify how the users default web browser should open up - either normally, minimized, or maximized. Its set to SW_SHOWNORMAL by default, which is fine for our purposes.
Constants
SW_SHOWNORMAL is a constant. A constant is just a name that represents a value, essentially becoming an alias for that value. Constants are often used to represent numeric values in parameters. Its easier to remember what effect SW_MAXIMIZE has than it is to remember what happens when you pass the number 3 to the action.
Tip: The File.OpenURL action can also be used to open local HTML files. Just click on the URL parameter, click the browse button, and use the Select File dialog to select a file. The file will be copied into your projects Docs folder and accessed from there. (Note that if the local html file has any links to other local html files, you will need to copy those files into the Docs folder on your own, or the links wont work.)