If you add more than one leg to the trip, changing the status of any of these legs will result in changing the whole trip status.
For example: a trip consists of 4 legs - 2 legs on 12-08-2013 and the other 2 on 14-08-2013. All legs have been assigned with the status 'Option' and all of the have the same 'Quote number': 123
When you change the status of the 1st leg to 'Flight' (i.e. option has been confirmed) - all other legs will have the status changed to 'Flight' as well.
The same applies when i.e. 3 legs of one trip have the same Quote number:123 - but the last leg has it different :456 - when changing the status of the last leg from 'Option' to 'Flight' it will result in changing the status of the other 3 legs to 'Flight' as well. Please see the sequence below: