Allocation of requirements from/to diagrams or tables can only be performed in the Properties view when the diagram is selected, it is not possible to create allocation links from/to diagrams or tables when a Requirement is selected,
For performance reasons, when a Requirement is displayed in the Semantic Browser allocated/allocating links to/from diagrams are not displayed (they are displayed, as expected for model elements),
Allocations links or Internal Relation links can only be created from elements in an architecture level to elements in the same architecture level or in an upper architecture level in the same model,
In a Project/Library, the Requirement model can not reference elements from a referenced Library (e.g model elements, Data Types, Attribute Definitions...). Anyway, it is possible to create Allocation links or Internal Relation links inside a library seen from a model/library in Read/Write mode,
Requirements allocation can only be done on elements belonging to the Capella metamodel or an inheriting Metamodel (+ Sirius' diagrams and table). If additional Viewpoints are used, they must inherit from the Capella metamodel to work with the Requirements Viewpoint,
There is no way to export elements of the Requirements VP. So changes done in the Requirements model (changed/created Requirements, created Allocations or Internal Links...) will stay in the model and it will not be possible to export them in a Requirement Management tool (e.g. DOORS).