Bug#750818: It gets weirder

[Johan Spee <web@coonsden.com>]

I did some more testing:

I sent some messages to myself and they all ended up 'in duplo' in the target 
mailbox (i.e. the mailbox the filter is supposed to move the message to).

When I next 'trash' the duplicate messages the trash mailbox only shows one, 
single copy.

I next empty the 'trash' mailbox and open my inbox: a single copy of the 
message re-appears in the target mailbox!

I trash that message and it disappears,  but the trash mailbox remains empty.

When I open my inbox it is back again, in the target mailbox.

This goes on forverer.