Yosemite has no sort by name in Mail
Yosemite has what I would say is a bug- it is certainly at least a dropped feature.
I'm sure that most people view mail sorted by date as do I. But sometimes I want to view all mail from a particular sender. All previous versions of mail allowed you to simply click on any mail in the inbox and then simply click the "sort by name" tab at the top to see all letters sorted by name, beginning with the selected email. Now in Yosemite, instead of beginning with the selected email, it instead starts at "A" or "Z" ignoring the selected email. I would suggest that this is helpful to exactly nobody. I'm hoping this is just a bug/oversight that will be quickly fixed. "Sort by name" is king of important to those of who are heavy users.
And yes, I understand that I can do a search. But this brings up every email that even mentions the sender and searching and then sorting is super cumbersome compared to the one click method that has seemingly been abandoned. Hoping there's a fix in sight!