Contextual links can't handle multiple occurrences of the same contextual links

Updated: Comment #0

Problem/Motivation

Discovered via #2075185: When an entity is in-place edited (i.e. saved), other instances of that entity on the same page are not updated (no propagation).

When the same content appears more than once on the same page, that content naturally has the same contextual links (specifically, exactly the same contextual links placeholder, e.g. <div data-contextual-id="node:node=2:"></div>). Each contextual link should work correctly and act independently, of course.

However, that is not what happens. In the current codebase, when opening one contextual link (by clicking on the pencil icon), the other one will be opened as well, because they share the same state.

Steps to reproduce:

1. Create an article node.
2. Expose the frontpage as a block in the sidebar.
3. Go to the frontpage. The same node now appears twice: once in the main content area, once in the sidebar. Click either contextual link. Both contextual link menus will be opened.

Proposed resolution

Fix this.

Remaining tasks

None.

User interface changes

None.

API changes

None.