This option on the Admin->Features panel controls whether modules can be shaded or not. When a module is shadeable, clicking on the show/hide module contents icon in the module's title bar, or double-clicking the module's title bar, will flip between only displaying the title and displaying title plus the module contents, for that user.
Settings
There are three settings:
Always - all modules in columns are presented with the shade button
Module decides. This is the default
Never - no modules in columns are presented with the shade button
Module decides By default, the application menu is shadeable, other menus and modules are not. Administrators can turn on the shade button - on a module-by-module basis - by putting 'flip=y' into the parameters box on the Admin->Modules panel.
MODULE plugin By default a module called via the MODULE plugin follows the same rules than the column modules. But if a user specify the module param flip with a value y or n, this behavior overwrites the default one.More PluginModule