I have the delete shortcut ready for shader effects like the other stack UIs,
but because they're missing an update notification it doesn't work properly.
Theoretically this should be done whenever a context for the properties editor
The main thing I wanted to check on is whether I defined ND_SHADERFX in the correct place in WM_types.h.
But also, @Antonio Vazquez (antoniov). I checked viewport cycles and EEVEE rendering and it all works, so I'm
assuming I have the update in all the necessary places.