Understanding the Inheritance hierarchy in OOP

Question

When Looking at the inheritance hierarchy trees in OOP when two objects are side by side in the diagram what is their relationship to each other? For example: NSWindow and NSView both inherit from NSResponder, so are they siblings? How do their respective methods relate?

Answer 1

The only relation you can tell from the diagram, is that they have the same parent. The only thing that you can surely tell is that they share what they inherit from their common parent.

As they are so closely related, there are probably other similarities, for example their purpose. However, that is not evident from the inheritance tree.