Learn how to change the parameters of standard connections within a custom connection instance without impacting the definition of the custom connection.
Inside the custom connection edit mode, you can select a nested standard connection within a custom connection. Click Modify | Structural Connections tab 
Connection panel (Modify Parameters) to open the specific connection dialog and change parameters. The nested connection is changed for all instances of the custom connection type.
If a custom connection contains steel parts (like plates, bolts, and welds), some part parameters are available and can be changed separately for single instances of a custom connection. Tab select sub-elements of a custom connection to view their parameters in the Properties palette.
Most of the parameters of the steel elements that are not controlled by a standard connection inside a custom connection, can be modified in the Edit mode of the custom connection. These parameters are modified for all instances of the custom connection.