Method for designing Layout
Description
This dropdown property has two options for designing a Layout: Genie and Freeform. All layouts are edited on the Form Layout pane, which also has a genie/freeform radio button option for design. If you choose 'genie' option as the 'Method for designing Layout' on the Multiple Layouts pane, you will see the genie open for that layout on the Form Layout pane; and likewise for the 'Freeform' option.
A Layout named Layout_B using a Freeform method for design.
Layout_B viewed in the Form Layout Editor, the Freeform editor is assigned to that layout.