modify system script

Dear SIrs

May i confirm the steps to update system script on IDM, assuming I am try to update ADS_PersonUpdate_ADSaccount script

1) locate the script ADS_PersonUpdate_ADSAccount under overridable scripts node from Designer/Script Library

2) open ADS_PersonUpdate_ADSAccount script , then click copy script ADS_PersonUpdate_ADSAccount under task panel.

3) rename ADS_PersonUpdate_ADSAccount1 to CCC_ADS_PersonUpdate_ADSAccount

4) CCC_ADS_PersonUpdate_ADSAccount is showing under Overriddenscripts node

5) then i just put a comment line start ' and save the script CCC_ADS_PersonUpdate_ADSAccount

6) while  I am trying to compile the database, i have encountered the following error

I got this error

Designer 

1

[System.NullReferenceException] Object reference not set to an instance of an object. at system.Windows.Forms.NativeWindow.Callback[IntPtr,wparam,IntPtr lparam) at System.Windows.Forms.ComboBox.WndProc(Message& m)

I have tried the other error, this error also pop up, may anyone has any idea what is the cause, what I have been done incorrectly for IDM?

Thanks
Gary