- Does it do something to exactly one opened object? It will be in the editor of that object.
- Does your action involve more than one object, or is it not particularly related to an object in In short: The header contains global actions, while the editor contains actions relating to the content of the editor.
A few examples:
Compile all components in the repository. This is an action that is not bound to exactly one opened component. This compile action can be found on the main menu in the header.
Compiling a component. This is an action for an open object in the component editor, so it’s to be found somewhere in the editor. Of course, it is also possible to compile the same component from the compile option in the header. The result is the same.
Export all child objects from a project. The boundary of this action is the project’s content. Therefore, it is to be found in the project’s editor.