Moved some of the plates around so that the last friction plate now sits further into the basket so when the pressure plate is released it dont fall out.
When I first put a slipper in my 996 we'd built the clutch pack and it worked a treat, was only on the way down to Brands a few years ago it started to slip (only done about 150 miles or so) had to get the bike AA'd back home and continue the journey on the back of a Blade, turned out as the clutch started to wear ever so slightly the pack reduced in size enough for it to slip