I made a dialog form where user can set username in EditBox. Another way I supported is to choose user through standard IDsObjectPicker invoked in custom action binded to "browse" button on this form (after doing this action I call standard action, that set binded property to new value). It works if I simply use "browse" button - but, if I initially try to edit value in EditBox, later browsing for user doesn't set new value. These is two message in installer log:
-- this message caused by setting property atfer browsing for user
MSI © (E0:50) [14:57:52:406]: PROPERTY CHANGE: Adding SERVICE_USERNAME property. Its value is 'NewValue'.
-- I can't recognize what reason cause this action

MSI © (E0:50) [14:57:54:843]: PROPERTY CHANGE: Deleting SERVICE_USERNAME property. Its current value is 'OldValue'.
Any suggestions?