Add count on action window domain
It could be useful to the user to show on the tab the number of records inside.
This is especially useful for tab which normally should have no record, so the user can see before clicking on it if there is something to do.
The difficulty about counting with a database query is that it forces the database to read all the records to count. So if you make the server counting for domain that returns a very large number like the "All" tabs, it will have a very poor performance. For that, I think counting should be an opt-in option of the window domain.
Also the query should be done in background like the attachments or the notes counting to not interfere with the user work.