andyb13, thanks for bringing this up. This is partly by design, partly a bug, and I have an easy workaround.
First, the part that is by design: the monitoring plugin can automatically log unhandled exceptions. This is enabled by default but e.Handled is set to false by default in order to let the main app handle the exception. The good news is that these behaviors
can be controled through a config file (see the workaround below).
The bug: If your own app handles the ApplicationException event first and sets e.Handled = true, the monitoring plugin will go and set this back to false (depending on the config). It should set it to false only if your app has not handled it. I will
make sure this is addressed in the next release (SMF 2.5) due in a couple weeks.
The workaround: create a monitoringconfig.xml file and change PreventUnhandledExceptions = 1:
Please refer to http://ecn.channel9.msdn.com/o9/content/smf/howto/v2/documents/HealthMonitor.docx for more info on how to create a use a custom MonitoringConfig.xml file.