I do find a lot of cases that I’m responding to require setting up a new script.
The interfaces are really easy to implement (and extend).
They only provided a basic set of “out of the box” controls, for everything else you have to build your own.
Looking at the source (https://bitbucket.org/Unity-Technologies/ui/src/5fc21bb4ecf4b40ff6630057edaa070252909b2e/UnityEngine.UI/UI/Core/GraphicRaycaster.cs?at=4.6), the Blocking options only affect the UI canvas raycasting. Does not affect the rest of your 3D scene.
The CanvasGroup is supposed to block raycasts, so it is odd that it isn’t. Will investigate further.
Note the UI Extensions post on the forum, I’m managing a bitbucket repository with a host of community built controls to fill in gaps.
Simon (Darkside) Jackson