It just took me a long time to figure out why background blur “wasn’t working”. You need to set the fill opacity (! not appearance opacity) to some value less than 100%. This is not intuitive.

Suggestions:

• Do what XD did. Make the background blur appear the instant you set the object to “Background Blur”
• Do something in the UI to make it clear you need to adjust other settings before the blur will work. Don’t make me hunt the internet to figure out basic functions. Make the UI self-explanatory.