Hi Michael,
The randomizer, and most of our addons, is not yet updated for 5.5. When it is, expect it to show a stack instead.

If you want to know if an add-on is 5.5 ready, look it up in the "Browse Add-Ons" part of the Dashboard.

I was wondering this too...now that 5.5.1 is out/stable will this work as-is, or will an update be needed before it will even work at all?

thanks,

this has now been updated. upgrade to 5.5, update your add-ons, randomizer should work fine from stacks and scrapbooks