This is not as intuitive for some people as was hoped when the PowerStrip interface was designed: whenever possible, PowerStrip provides separate controls for each monitor
that appears in Windows Display Properties > Settings.
If you have two or more independent monitors in Windows Display Properties > Settings, you'll find independent controls in PowerStrip too.
For example, a Matrox Parhelia with two monitors attached will have one set of Performance controls, but two sets of Color and Display controls. If you add a PCI Matrox G200, PowerStrip will offer 2 sets of Performance controls, and 3 sets of Color and Display controls.
To cycle the controls from one "monitor" to the next, use the Device selector
at the top of each dialog box, just below the Minimize/Close buttons.
Beginning with Build 376, you can also simply drag a PowerStrip dialog box from one monitor to the next, and the relevant controls will be updated and associated with that monitor.