no root file system after encryption

[Juha Heinanen <jh@tutpro.com>]

I'm trying to install debian jessie with three partitions: /boot, /, and
swap.  i'm able to create and encrypt the partitions fine, but when I
then try to changes to disk, installer complains:

  No root file system defined, please correct this from partitioning menu.

The second partition had / as its mount point before the encryption.
Why was it lost?  What is the correct procedure to create the encrypted
partitions?

Also, looks like it is not possible to correct anything from
partitioning menu because of the encryption.

-- Juha