diff --git a/vncviewer/vncviewer.man b/vncviewer/vncviewer.man
index b1450d1..e48a0c4 100644
--- a/vncviewer/vncviewer.man
+++ b/vncviewer/vncviewer.man
@@ -275,6 +275,10 @@
 \fIR\fR, and \fIG\fR taken the values of the local port number, the remote
 host, the port number on the remote host, and the gateway machine
 respectively.
+.
+.TP
+.B \-AlertOnFatalError
+Display a dialog with any fatal error before exiting. Default is on.
 
 .SH FILES
 .TP