Change calender for event & multiple events in the same time slot

I'm using this app with multiple google calendars. Sometimes it happens that I choose the wrong calendar when creating an event. At the moment I see not possibility to change the calendar once the event has been created since in the event properties the calender choice is disabled.

And when dragging events it's not possible to drag an event to a time slot at which another event is already created (no matter if it's the same calendar or another one). However, when editing an event, the time can be set to that particular time slot in the event properties. It would be nice if this could be done also by simply dragging an event.

Apart from that: great app.