To edit Variable Options, go to Tools -> Options -> Automise -> General.
Variable Sense allows you to see a drop-down list with possible completions for variable names:
The list opens automatically when you type % to begin entering a Target Parameters.
When you hover your mouse over an text field or memo box on an action's property page, you will see a hint field with all of the variable references in that field expanded:
You can choose to use either the Variables' Default Values, or their Current Values, during this expansion.
Non-persistent variables are reset to their default values each time a project is run. By selecting these options, you can also choose whether they are reset when running part of a project.