I am attempting to use the before close event in VBA to perform some data
integrity checks, however the Cancel variable which is supposed to abort the
workbook close event does not seem to be functioning as intended. I created
a simple test (blank workbook, no other VBA except what is shown below) to
try this out and again it failed. Debugging, it appears that the variable is
indeed being set to correctly however setting it to true or false does not
cause the close event to cancel. Since I've used this code before, I'm
wondering if this is a bug or I just woke up too early this morning.

My version info is Excel 2003 (11.6355.6360) SP1, VBA Retail 6.4.9972.

Private Sub Workbook_BeforeClose(Cancel As Boolean)
MsgBox("No you can't.")
Cancel = True
End Sub