Suppose I have two different presentations I've opened in Impress, and two different monitors connected to my computer. I would like to be able to "slideshow" both presentations at once on my two monitors, without them interfering with each other. AFAICT, this is not currently doable. Notes: * This bug is not about how exactly the progression through each of the two slideshows is to be managed. * This is a part of the ask in bug 160242, which combined too many things it seems.