We just had a requirement come up on my current project where they wanted to restrict the number of sublayouts of a certain type on a specific page. They are using the unified page editor, so the thought was that when the "Select a Rendering"...
Over the weekend, I posted part 1 of a discussion of this thing I created that I’m calling “conditional pages”. I promised to elaborate on the technical details, so here I am with some code samples and instructions that hopefully will allow others to reproduce what I have done....