TwinColSelectFieldDefinition renders two boxes side by side. Available items are in the left box and selected items in the right box. To select an item, move it from left to right. This control is useful for selecting large sets of items such as group and role memberships. You can find an example in the Security app.
Here is an example of a custom GroupManagementFieldDefinition field which extends TwinColSelectFieldDefinition . This field is used to assign groups to a user.
Assign user to groups
Other available groups
User is a member of
You can use all common field properties.
Properties specific to the twin-column field.