Request was posted 4 years ago asking for Custom Attribute syntax for "use last value".
Has this been implemented yet? In my case, I want Plant Area once selected to not change until another area is selected.
http://communities.bentley.com/products/plant/design___engineering/f/5927/p/75258/202435#202435
Use Last Value
Currently there is nothing for “use last value”. Please create an ST with all requirements. We can evaluate and schedule for possible implementation.