This open source plugin support create generalization set between classes in Visual Paradigm's UML class diagram.
Details about how to deploy this plugin to Visual Paradigm can be found at https://knowhow.visual-paradigm.com/openapi/how-to-deploy-plugins-to-vp-application/
The generalizatio set can be created using the IGeneralizationSet model element. Once the IGeneralizationSet being created, user can add generalizations into generalization set. User can also use the IGeneralizationSetUIModel.setNotation() method to specify its presentation.
More details about this plugin can be found at https://knowhow.visual-paradigm.com/openapi/generalization-set-2/