[al_f]

According to the ninjas the current behaviour is a compromise to try and accommodate some fairly disparate feature requests they've had about this. A workaround that Brian from Omni suggested to me is:

select a next action in Project view
go to format > copy style
select an available action in project view
format > paste style

Then all your available actions will appear the same as next ones. If you don't like purple you could do it the other way round I suppose. :)