I added several buttons with toggle-actions (showing just one expl. below) to full calendar list view, but none of them is clickable. The togglePublic-function is available and I also made the height 1 point higher than event-click-layer via z-index.
Just the event-click-action is triggered.

eventContent: (arg) => {
      let paragraph = document.createElement('div');
      let public = document.createElement('div');

      paragraph.className = 'event';
      public.className = 'public';

      if (arg.event.extendedProps.public === true) {
        public.innerHTML = '<button style="width: 36px; height: 36px; background-color: green; color: white; border: 0; border-radius: 18px;" (click)="togglePublic(' + arg.event.id + ')"><i class="material-icons">public</i></button>';
      } else {
        public.innerHTML = '<button style="width: 36px; height: 36px; background-color: red; color: white; border: 0; border-radius: 18px;" (click)="togglePublic(' + arg.event.id + ')"><i class="material-icons">public</i></button>';
      }

      paragraph.appendChild(public);

      return { domNodes: [paragraph] };
    },
    eventClick: this.openEditEventDialog.bind(this)