It works fine for me on a Flame (I could take a screenshot if you like). I'd rather not use a Toaster in the management UI (although that's what I used to do actually), since then I'm doing the same thing twice in slightly different ways; we'd also need different strings for each case.

In the longer term, the Notification API is probably going to get a "transient" flag that makes it work like Toasters do now, and we'll remove the Toaster helper entirely.