[horde] 'Alternative' should be the Default

[bin at crewecleanteam.co.uk]

Hello,

When I receive an email, it is always in plain text.  There is an
'alternative' button available when I 'show all parts'.  If I click on
this I then see the message as expected - with colours, pictures, etc..
 This is the same in Chrome, Firefox, IE.  How can I make the
'alternative' view the default?

Thank you,

Dave.