In android studio, in design section, Layouts and Containers are categorized separately.
What is the fundamental difference between them?
Layouts all directly extend ViewGroup. The Layout suffix is part of the class name for classes in this group, e.g. LinearLayout, RelativeLayout.
Containers is a bucket description for Views that wrap dynamic content. They are more specialized than Layouts and can but don't have to extend a Layout. Some extend ViewGroup indirectly e.g ListView, some don't e.g. VideoView. The Container label is used in Android Studio but is not part of the class name.