By user requests we have added functionality for easy extraction of GSP text to resource bundles. To do this you can select a text fragment, press Alt+Enter and choose the intention "Extract selected text to messages.properties": I18nize String dialog will open: This feature is available in IntelliJ IDEA X #98.231

Now IntelliJ IDEA X is able to debug GSPs. You can set breakpoints and view variable values or evaluate expressions.

As you already know, we are working on GSP editing improvements in IntelliJ IDEA X. In particular, now the editor knows about the variables that the controller supplies to the view. Example: Consider an action returning a bookList variable: And the corresponding GSP file has access to this variable: Rename, completion and find usages work as they should.