Dear all,
Since a while i can no more switch the month in the calendar.
When I hit the → or ← button in the title row with the month name, the module closes immediately.

What can be the reason for this?

After experimenting with settings...
It turns out that 'single click' via Wacom tablet pen creates this effect.
When using the mouse everything is OK...
With the pen I need to use double click function.

There are websites, for example my newspaper sites, in which the table also does not behave, so this is a 'common' problem on my system...

This seems to be a known phenomenum:
https://answers.microsoft.com/en-us/win ... 533bde2f83

That's great information. Thank you for following up with your own solution.