Allow Singles to be part of a Structure & Channels to have a Single as an Index #17959

In my client projects I often encounter the following issues:

1. Clients have a hard time to understand the overall architecture of the page
2. When I have channel entries, it is hard to create breadcrumbs when the channel is nested (you could create it by splitting the path, but what you really want is the relation to the parent entries - for titles, etc.).
3. When I have channel entries, I want to have a back button.

Current Hack

At the moment I (and other members on discord) solve this by the following patterns:

• a Global Field where you can set references to Index Entries in a Structure or Single (Blog Index, Events Index, etc.)
• A big structure that keeps all the pages (for the client)

Possible Solution

Obviously this has a big smell. In order to solve this, I want to suggest the following idea:

1. Allow Singles to be part of a Structure (dropdown like the filesystem select) optionally
2. Allow Channels to select an Index (Single) optionally

Improvements & Chances

That would enable the following workflows:

• Create a "Pages" Structure that defines the hierarchy
• Add Singles to it (Homepage, Contact, Blog Index) that cannot be deleted
• Channel Entries now know where they are located and we can programmatically create sitemaps, breadcrumbs, back buttons
• Clients could see a Unified Content View, you could show a complete tree for things, in case these relations were set
• You can create back buttons and have the complete tree accessible in the breadcrumb

Related:

• Custom sources that combine singles/structures/channels should keep the structured view in the CP. Or there should be a way to view the sites structure (sitemap) in the CP #17683
• Ability to set the parent of a single #9373

Examples

Structure with Singles. Maybe an indication for indexes and singles

Possible Unified Content View, because Singles know their Channel Children and the Structure defines the hierarchy

Single with Owner/structure Select

Channel with Owner/Single/Index Select