It is now impossible to selectively quote small pieces of text (which used to appear indented) and respond to them.
Why would you? you'd be quoting text that was already quoted, not the text of the message you're replying to (if I understand this).
If you must, can you open the ellipsis and select them in the original message, before clicking reply? I have to I haven't sought an example to try this with.
Not only that! I just tested this with a reply via email, and nothing is collapsed in the email.
None of this collapsing of quotes ever applied to Individual emails, nor should it IMO.
Collapsing is for the web interface, eliding in the digest.