-Each 'log' subbranch contains an optional 'filename' property
-(defaults to "fg_log.csv"), an optional 'delimiter' property (defaults
-to a comma), an optional 'interval-ms' property (defaults to 0, which
-logs every frame), and a series of 'entry' subbranches. The
-'delimiter' property uses only the first character of the property
-value as the delimiter. Note that the logger does no escaping, so you
-must choose a delimiter that will not appear in the property values
-(that's not hard, since most of the values are numeric, but watch for
-commas in the titles).
+Each 'log' subbranch contains a required 'enabled' property, an
+optional 'filename' property (defaults to "fg_log.csv"), an optional
+'delimiter' property (defaults to a comma), an optional 'interval-ms'
+property (defaults to 0, which logs every frame), and a series of
+'entry' subbranches. The 'delimiter' property uses only the first
+character of the property value as the delimiter. Note that the
+logger does no escaping, so you must choose a delimiter that will not
+appear in the property values (that's not hard, since most of the
+values are numeric, but watch for commas in the titles).