@Alex: Thanks for the feature request, looking forward for it.
I will have a look an the getter, thank you very much for the input.
@Animal: Thanks for the css code snipped, this was also our idea only downside was that if the indicator is over an event the background-color is visible like that:
Screenshot 2022-07-26 121455.png (4.18 KiB) Viewed 498 times
That was the reason to ask if there is any option to use a custom html.