Managing projects - IntelliJ IDEA in Action - page 139

Figure 4.23
Enabling the Show Structure option in the
Project tool window dedicates a portion of
the tool window to a more detailed view
into the class currently open in the main
editor window.
structure fun, IDEA provides a dedicated tool window (the aptly named Structure
window). We'll discuss the particulars in chapter 9 when we talk about analysis
and refactoring.
Showing modules
The Show Modules option is available only in the Packages view. Enabling it
adds the module structure pack to the Packages view, grouping packages under
their parent module. Even if two modules share common packages, the class files
appear only under the module whose source path they're defined in.