ok so I have tested this twice so dont take my word as gold but I think I have figured out the first gen 12.9 multitasking and floating app glitch. So I tried 2 different scenarios 1: Put a floating app on an already split view screen. This causes the floating app to be active and the split view to be grayed out. THIS DOES NOT WORK AND MAY BE A BUG 2: Have one app full screen, then put a floating app in front of the full screen app. Then from the dock drag a third app into split view on the left side. THis should allow all three apps to be active. People test this to see if its just a coincedence or if this is actually a repeatable thing.