If someone want's to filter activity stream the nothing happend while I see a javascript opening left below in screen - see screenshot

Hi
the filter option is working on your site prntscr.com/ijr8b1
The default filter option has some js conflict with the template or 3rd party extensions.
If you allow me I can disable the extension one by one and let you know the details on it.
As its a live site I am unable to disable any extension on your site.
You can also test it by disable extensions and check this issue with default Joomla template.


Regards

woud it be possible just to hide or disable the default filter option (right icon) ?

Hi
Add below code in your template.css fie

.joms-activity-filter__options {
    display: none;
}