>Where is the NODEFAULT keyword in the MSDN help? Using Index tab to search for the word, it points me to the right keyword, but pressing ENTER, it points me to DEFINE CLASS.

Its a clause of DEFINE CLASS. My guess: to be more modern, you shouldn't be adding more commands to the language, just methods. Thats why the NODEFAULT got turned into a clause of an existing command. And it couldn't be a function, because your not calling some code with a return value, your preventing code.

>...but if Cancel, closing will not continue but clicking Save or Revert button again, it does not perform the behaviour we want. It doesn't enable or disable the controls which is normally Ok.

Can you explain this again? The code you posted does touch any controls like you describe here.