I selected "View -> Hide Read Messages", then deleted the remaining unread
messages after reading them.  After deleting the last one, the message list
panel displays: "There are no messages in this folder". This is incorrect, as
there are many hidden messages.  Some are hidden because they are read, and
some are also hidden because they have been deleted (but not yet purged).

It's fine to get a notice like this if the only messages are deleted messages,
but I think these semantics are confusing with regard to messages that are
temporarily hidden.  There should be some indication in the message list panel
that some message are hidden, especially if the list is empty.

Evolution version is 2.26.3