DESIGN SPIKE: Enable post to ‘Only Me’ within a restricted group context.

### User stories: ###

1. As a USER I want to be able to ‘post to me’ within a restricted group.
2. As a USER I need an easy way to be able to view my 'only me' annotations within a given context.
3. As a USER I would like to be able to easily annotate to groups I have permissions to annotate in (which may be outside the scope of the current group).

### Context ###
Posting to ‘Only me’ was de-scoped from #489 'Launching the sidebar when I am in a restricted group'. The rationale behind this was to implement an interim solution which provides a better experience than the one we have at present (i.e users are being walked into an error message when they try to post to a restricted group).

### The Problem ###

1. Currently in open and private groups, users can annotate freely either posting publicly, to a subset of users (in a private group) or to 'only me'. In the new restricted groups model, users will lose the ability to post publicly but we should retain the ability to accommodate the ability to post to 'only me'.

2. Presently posting to 'only me' results in annotations being shown in-line and they 'live' within the group scope they are written in, albeit visible to only 'me'. This issue was previously documented here: https://github.com/hypothesis/product-backlog/issues/200

Questions:

- Do we move the scope of 'only me' annotations out of the group context? This has big implications technically and for the user.

- If we move the 'only me' annotations out of a group, will they go into a separate bucket/group accessed by an 'Only me' option within the group control or do they continue to be associated with the group and visible in-line?

- Is there a way to do a hybrid solution between what we have currently and allowing users to access their 'only me' annotations independently of a group?

- If one of the user needs as mentioned in #200 is: "I want to quickly and easily see my own annotations (and no-one else's) on any page". It is possible to meet this need by having 'Only me' be a filter and not a layer in the group scope control.

The biggest challenge we have to solve from a user perspective is when we remove 'only me' annotations from being associated with a group, where does an annotation go after it's posted i.e. does it disappear off the screen? The user will be continually switching contexts between the default publisher group and their 'only me' annotations if we remove them from the group context entirely.

**Pros** of keeping ‘only me’ within the currently selected group scope:
- It’s the model we have now and what users are familiar with.
- It helps keep the ‘post to me’ contextually relevant and easily accessible within the context of a group. It doesn't force users to context switch to view their recently 'posted to only me' annotations.

**Cons** with keeping ‘only me’ within the currently selected group scope:
- What if I would like to view just the ‘only me’ private annotations? There is no easy way to do this at the moment.
- Storing the 'only me' annotations under the scope of a group isn't ontologically correct. The annotations are associated with the content itself, the currently selected layer is arbitrary.

### Questions: ###
- What happens to the annotations if the group is deleted, where do the annotations live?
- Is there a way to store the 'only me' annotations outside of the currently selected group scope but allow them to be visible on the screen at the same time, and co-exist with the same view as the current group scope for either the current session (until the user navigates away from the page or refreshes).

### Proposed Solution ###

_1. Update adder to allow write annotations/highlights_
- The 'original' adder is shown with both the ability to annotate and highlight enabled.


_2. Post to button enabled_
- When a user clicks to annotate, the 'post to' button defaults to 'Only me', the split button options are: Post to Only Me and Post to Hypothesis 'public' layer. (TBD)


_3. The annotate text field scope is updated from Group -> Only Me_

**Current scope shown below for reference.**

**Updated scope**

_4. Revised sidebar when annotation behaviour includes posting to me/hypothesis public within a restricted group_


### Considerations ###

Should the 'only me' annotations 'disappear' from the current view and be located within an 'only me' layer accessible through the groups control, or should we persist the 'only me' annotation for the duration of the session in order to minimise context switching for the user?

_5. Revised group control incorporating 'only me'_

**Questions:**

- Does 'Only me' have an associated activity page?
- Do we continue to 'interleave' only me and group annotations within the same view?
- Will it involve too much context switching for users to select 'only me' within the groups control to view their annotations?
- If so, how long should 'only me' annotations persist? Suggestion: for the duration of the session or after a page reload, 'only me' annotations are found within the 'only me' layer.