Hi Witold,
Thank you for your interest in Syncfusion Products.
We have created a simple sample to depict how to create and add new ports to a symbol during run time and the same can be downloaded from the below link.
Sample-1709928619.zipUsing the Ports property in the property editor, different types of ports can be added to a selected node. Alternatively, you can select a node and right-click on it to add new port.Kindly try the above sample and let me know if it helps.
Please let me know if you have any concerns.
Regards,
Pandi Murugan A