Microsoft PowerPoint freezes a running slide show when you start editing it or do any other work. The logic behind this behavior seems to be that if an application is launched from a running slide show, then the slide show should freeze for the time that application is running. With multiple monitor setup, this kind of behavior may not be desirable. Multi-monitor setups should enable us to edit a presentation on one monitor while the slide show is running on other monitor. Among other things, PowerShow add-in enables you to do exactly that.