Changes have been made in Git (master):

commit dcef41d425941fabafc63d201ad416178caef34d
Author: Jasper Olbrich <Jasper.Olbrich@students.uni-marburg.de>
Date:   Tue Aug 12 13:58:36 2014 +0200

     Fix error when all day event is hidden

     Signed-off-by: Jan Schneider <jan@horde.org>
     Bug: 13433

     Conflicts:
             kronolith/docs/CHANGES
             kronolith/package.xml

  kronolith/js/kronolith.js |    2 ++
  1 files changed, 2 insertions(+), 0 deletions(-)

http://github.com/horde/horde/commit/dcef41d425941fabafc63d201ad416178caef34d

Thanks!

Changes have been made in Git (FRAMEWORK_5_2):

commit 566a6cb44bccc653951c69007c58bcabc5a94ed2
Author: Jasper Olbrich <Jasper.Olbrich@students.uni-marburg.de>
Date:   Tue Aug 12 13:58:36 2014 +0200

     Fix error when all day event is hidden

     Signed-off-by: Jan Schneider <jan@horde.org>
     Bug: 13433

  kronolith/docs/CHANGES    |    2 ++
  kronolith/js/kronolith.js |    2 ++
  kronolith/package.xml     |    2 ++
  3 files changed, 6 insertions(+), 0 deletions(-)

http://github.com/horde/horde/commit/566a6cb44bccc653951c69007c58bcabc5a94ed2

If a user has limited the number of events to show in month view, the 
following error can occur:
TypeError: elm.retrieve(...) is undefined

To reproduce:
1) Create more than max_events all-day-events on one day.
2) Navigate to the next month and back again.
3) The TypeError occurs and the JS on the page stops working.

I assume that this is because (~ line 1616 in kronolith.js)

                                         var elm = allDays.pop();
                                         elm.purge();
                                         elm.remove();

here an element from the events array is destroyed, but the reference 
is still contained in the events array. For me, the attached patch 
seems to fix this.