Studio View > Inspector in Atelier?

You can use the Outline view in Atelier for information about the current class' properties, parameters, class methods, etc:

There is an enhancement request to show inherited members in the Outline view which is currently planned for Atelier 1.1.

Atelier's code completion, which can be accessed by hitting ctrl+space, is also a good tool here. For example you can use code completion to quickly check the possible options for an index's keywords (with documentation):