Locking: customized window "lock is in used" is not shown

Initial behaviour:
--------------------------------------------------------------
I want to add a customized XDEVWindow which is shown when user can not get lock because a other one has it already.
--------------------------------------------------------------

Real behaviour:
--------------------------------------------------------------
I can add a customized XDEVWindow but the default one is shown.
--------------------------------------------------------------

Expected behaviour:
--------------------------------------------------------------
Show the customized dialog.
--------------------------------------------------------------

Comment:
--------------------------------------------------------------

--------------------------------------------------------------