Calender doesn't allow to change month

Can you try this calendar module with changing to e.g. protostar (an official joomla template).
If then the calendar module works, you will know, the interference comes from your template ("allrounder" I guess)

Yes our template is the allrounder.
For us it doesn't really help if compatibility breaks.
Even done dating isn't supported.
Can you please tell, in wich revision the calender was changed.

So with the hint "sth. with jquery" doesn't help me - it's too deep under the hood.

allrounder-3 seems just very old (2013) . And in forums I read of more problems with this template.
The change in the calendar module was from JEM 2.2.2 to JEM 2.2.3, but perhaps there were some problems why it was changed.

Hey, I think something was going wrong during JEM installation/update.
When I take a look at your module I am missing those arrows to change the month.
Take a look at www.joomlaeventmanager.net/demo/ I think they are not generated with jQuery, they are built via PHP. So eventually you should reinstall JEM or the single mod_jem_cal. Do you use any template overrides? Eventually you forgot some overrides? Take a look in Joomlaroot/templates/<yourtemplatename>/custom/html

Hi Egnarts,
thanks for your hints.
I exchanged the ..modules/mod_jem_cal with the last one which was working.
Calender shows up correct. But this isn't a solution.
Somebody should explain, why the top line of the calender doesn't work any more.
It shows Aug Sep Okt and not << Sep >>
Thanks for your help - hopefully a software developer can improve this part of the code.

So you surely have a backup. Go back and resrore. I think for you it is the only solution