Unable to filter Select Dialog on children of current entity

Case:
I think its a common scenario of wanting to have:

a to-one relation field to one of the child entities in another (collection) field of the same current entity.

  • For example, you have a project with tasks and you have a to-one select field in the project to perform an automation on one of these tasks.
  • Other example: You have a Page with child Versions, and the Page also has a to-one field to the ‘Current Version’ entity.

Issue:
The select dialog of the to-one relation to the single entity, cannot be filtered to only show child entities of the entity.
For example: the dialog cannot filter the selectable Tasks by the Tasks of the parent Project.

See below my attempts, which have failed:

Dynamic filter options are not helpful here:

Here I created a lookup to the parent Page its Blocks, to filter if the Current Block is part of it. that works, but only if the Current Block field already has a value.

Because if the Current Block field is empty, then it shows ‘There are not suggested Blocks’

WORKAROUND

So the more complex workaround is to create a third field as well as a lookup. So yet another to-one relation field in the parent Page to the Block db, which is always populated (automatically).

Are there other solutions that I did not see yet?

I don’t think you are missing anything. Potentially, dynamic filters could be extended to allow simply This Project.
Until then, some form of workaround will be necessary (e.g. an auto linking self-relation that links an entity to itself allowing This Project → Self as a dynamic filter).

However, I am curious about the use cases you mention:

What are the reasons for why you wouldn’t simply have a button on the Task db, so you could choose to execute some actions on a specific Task, without having to create a field just for this purpose?

Did you consider having a checkbox (manual or formula, depending on your use case) to allow you to mark (or calculate) which specific Child is the ‘Current version’?