Ponsonby: Metaslider widget on “Front Page” template

Hi there,

I’m trying to insert a Metaslider slideshow in one of the widget-areas of the Ponsonby front page template – in the

'2columns-center-bigleft'

to be exact. Unfortunately, the slider won’t stretch over the two columns, but only spans one column.

I’m using WP 4.3.1, a Ponsonby Child theme and the Metaslider Pro Plugin.
I’ve selected the “Stretch to 100% Width” in the Metaslider advanced settings.

Could you give me a hint on how to fix this or how to develop a workaround?

Cheers

Alex