Delete a class and remove its assignment from the model/drawing

An alternative method to delete a UDC (User Defined Class) and remove the UDP (User Defined Property) from the model/drawing, is to perform this operation from the File Properties dialog box (see also Delete UDC and Delete UDP). To do this, follow the steps below:
 
1 Open File Properties dialog box.
2 Select the Custom tab.
3 In the Properties list, select the UDP you want to remove.
4 Select Delete, and the UDP will be deleted and removed from the Properties list.