[Oberon] Native Oberon: compiler not marking errors

[Bob Walkden]

Hi,

I've been using Oberon and BlackBox on and off for several years now.
This week I installed Native Oberon 2.3.6 on bare hardware on a dedicated
PC (IBM Thinkpad 760ED). The compiler is detecting errors, and listing
them in the log, but it isn't marking them in the source. I've looked
for clues in the documentation, but have found none. Can somebody tell
me what I have to do/undo to get the compiler to mark the errors in
the source, please?

Thanks,

Bob Walkden