Use the 
Dim Inactive Components on the Graphics toolbar to toggle the display of active components in an assembly.When any component is activated, click Dim Inactive Components to view only the active components. The inactive components are dimmed. To display all the components in the assembly, click the icon again.
Dim Inactive Components on the Graphics toolbar to toggle the display of active components in an assembly.When any component is activated, click Dim Inactive Components to view only the active components. The inactive components are dimmed. To display all the components in the assembly, click the icon again.