Event disapears if ” date=’start date’ ” is used and start date has passed

I use your shortcode. If I have an event, e.g. for a weekend. I have a shortcode like this:
[ecs-list-events limit=’10’ thumb=’true’ thumbwidth=’39’ thumbheight=’26’ cat=’with Torben’ contentorder=’thumbnail, title, date’ key=’start date’ viewall=’true’ ]
events that have a start date in the past are not displayed any longer.

But if I change it to
[ecs-list-events limit=’10’ thumb=’true’ thumbwidth=’39’ thumbheight=’26’ cat=’with Torben’ contentorder=’thumbnail, title, date’ viewall=’true’ ]
I have removed
key=’start date’

…then the event is shown again.

I think this is a bug. Events that have a start date in the past should still be displayed, even though I activate the start-date-sorting. Only when the end-date pasted the event should not be displayed any longer.

I hope you get my point – otherwise, please ask.