From version 9.58 of the Calendar, support is added for placing comments in the
PHSM-Dates.dat and PHSM-Dates.txt files.

In PHSM-Dates.dat:
Any line in the PHSM-Dates.dat file that does NOT begin with a numeral followed
by a comma followed by another numeral and a comma and then some text like:
-10,1,text
will be considered being a comment.  It is recommended to start the commented
line with for example ; or // to make it more visible as being a comment.

An event can be commented out for future re-use by placing on or more non-
alphanumeric characters, like for example ; or // or & or # etc. in front of
the event - like:
; 1,1,New Years Day,,lime,,0

In PHSM-Dates.txt:
When saving an event from the "Change / Delete / Add Events" dialog all
comments in the PHSM-Dates.dat file will be transferred to PHSM-Dates.txt
with // in front of the comment (or the old event).  Using // is the only
way to make comments in PHSM-Dates.txt.

Note: Comments that are only present in the PHSM-Dates.txt file will not be
transferred to the PHSM-Dates.dat file, and will be lost when saving events
via the "Change / Delete / Add Events" dialog.

Recommended use:
Open the PHSM-Dates.dat file in a text editor (Shift+Alt+click on any date).
The lines can now re-arranged and comments can be added to your needs.  Save
the file and Ctrl+Alt+click on any date to reload the new PHSM-Dates.dat file.
Then double-click on any date with an event to open the "Change / Delete / Add
Events" dialog.  Now click the "Apply" button - this will transfer all the
changes in the PHSM-Dates.dat file to the PHSM-Dates.txt file with the correct
syntax.