One colleague asks this question:
In AG3 and HAM, the “Enhancement Component” button is missing in BSP_WD_CMPWB.

Answer
This is because in AG3 and HAM, the system is setup as “SAP system”, no extension is allowed in such kind of system.
The button is deliberately set as hidden in such systems.
Please try to practice extensibility exercise in dedicated system like QJ2 and QI2 instead.