Windows

Window

Windows are the main object in an app's interface.

Primary Windows

Primary Windows are what shows up when your app is opened, and displays the main functionality.

Primary Windows shouldn't depend on anything, closing one should not close others.
Apps should restrict themselves to one Primary Window.
All Primary Windows should be able to be resized.
Try to make the default size of your Primary Window match the desired amount of content your app needs.

Secondary Windows are used for complementary content to the Primary Window, such as About or Preferences.

Secondary Windows should always be modal to a Primary Window, appearing "attached" to it and centralized.
Closing a Primary Window should close any Secondary Windows associated with it.
Avoid stacking Secondary Windows.
Avoid complex content on a Secondary Window, and don't make it bigger than the Primary Window.

Primary Windows should be able to get to the extreme size of 360×266px for purposes of compatibility with mobile Linux users.