Custom elements are generic model elements for which the user can define functionalities in the Custom Element Type dialog.

 

The Custom Element Type dialog can be accessed by selecting Modeling Options from the Model tab of the ribbon, then selecting the custom element type from the Element types list on the Model Elements tab, and clicking the "New" or "View" button. To create a new custom element type, select Custom element types from the Element types list and click the "New" button. Optionally, you can also create a new custom element type from the drop down list accessible from the button next to the "New" button.