1) Visit <staff_url>/cgi-bin/koha/tools/holidays.pl
2) Select "Holiday only on this day" (or whatever other option to add an holiday). Click 'Save.
3) Now click on that day in the calendar, pick "delete this holiday". Click 'Save'. Notice the holiday is still there.
4) Apply patch. Repeat. Notice its deleted.
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com> Signed-off-by: Brendan Lawlor <blawlor@clamsnet.org> Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>