How to apply a custom forward renderer masking to UI elements

Hello would anyone be able to explain to me how to make my custom forward renderer features apply to UI elements? I saw and recorded this issue in my game yesterday:

If you do not prefer a video format: Here is a picture of what my "Only Visible in light" feature definition looks like. This feature is being applied perfectly to non-UI elements but the UI elements are not following it's rules. They always render no matter what. It is clear to me that UI elements need separate masking but I am not sure how to communicate the UI mask instructions from my custom forward renderer.

 

I understand that the Custom Forward Renderer writes to a stencil buffer. But is that buffer global, meaning could we access it from shader code? Is it's id the thing we are setting with the 'Value' slider?

 

Hello my friend, Jonas! That was exactly the solution. So in summary, it would seem that the layer of a UI element will not override its canvas layer (at least pertaining to rendering as you stated). It would be great to clarify that in the drop down selection of UI elements in the editor as this is not something I would have guessed on my own. I am very grateful for your aid. Thank you. @Jonas-Mortensen