add expense, make the default value 'portfolio cost'

When you add an expense it would save  time if the default value for property was 'portfolio cost' and you only had to change it if you wanted to choose a specific property. At the moment I have to change this field every time I add an expense but many of my expenses are portfolio costs so it would save a lot of time. I can't see much of a downside as you have to select an individual property anyway at the moment so it wouldn't add any extra clicks if you want to select a particular property.