Focus the first Window Where pcmanfm is Running

From the command line, what is the best way to locate the first window where pcmanfm is running, and then give that window focus? pcmanfm does not showcase it's application name on the title bar of the window in which it is running, so you can't focus it using wmctrl -a pcmanfm (which works for me in other applications that do indeed showcase their application's name in the window title bar). This is just one example, but what I'm really looking for is a better method of locating windows that are running a particular command, and then giving that window focus. The title bar method I've been using just isn't always reliable.