[Design] Editing Read-only items

[Philippe Bossut]

Philippe Bossut wrote:
> I'm trying to get a sense of how read-only items do behave right now. 
> Does anyone has a read-only ticket I could use for testing? 

Aparna gave me a ticket and I tried. So, for everyone's edification, you 
can edit anything in a read-only item. Apparently also the UI in the 
markup bar is broken and the striked crayon is not displayed.

So, right now, this is a rather confusing state of affairs for users 
indeed... We should at least repair the markup bar.

One proposal:
- if the item is "read-only", the markup bar shows a "striked crayon" icon
- nothing is editable when this icon is displayed but...
- ...the user can click the "striked crayon" to make the item editable, 
a dialog pops-up warning the user (edits will be local and conflict with 
edits coming from the server on sync) and the icon turns into a 
"non-striked crayon" (note that read-write item do not display any 
crayon of any kind so you can make the difference between a read-write 
item, a read-only item and a read-only but edited item...)

This seems to me the cheapest proposal for Preview (modifying the 
styling per attribute seems much riskier).

Cheers,
- Philippe