Using second monitor for a Slideshow

Running Lightroom 4.4 on my MacBook Pro, under OS 10.7.5. Slideshow runs great on computer. When I hook up second monitor I can see "desktop," and I can open a second window in LR on that auxiliary monitor. But, when I Play slideshow, on 2nd monitor it shows, then stops on first image, with no Identity plate slide, while show continues to play fine on laptop. If I switch to slideshow Preview all images appears on second monitor, again with no intro identity plate, but then eventually jump to next ones, with irregular timing & no smooth transitions.

Any ideas or suggestions? I need to do a presentation this evening.

Thanks.