Assembly Design > Using Assembly > Working with Assembly Components > Assembly Operations > Modifying Assemblies > To Activate a Component
  
To Activate a Component
1. In an open assembly, select a component in the Model Tree or graphics window, right-click and select Activate. Nodes in the Model Tree that are not the activated component are dimmed.
2. Click the arrow next to Operations to edit the active component. Use the shortcut menu commands that are available.