fields no longer side by side

Hi,

I’ve just noticed that somewhere along the line, some fields of this form are no longer displayed side by side: http://dekickvanhetkunnen.nl/contact/

However on this form all is well: http://dekickvanhetkunnen.nl/inschrijven/

What happend and most of all, how can I change it? I can’t find anything in the field of form settings to make this happen?

Thanks!

https://ww.wp.xz.cn/plugins/visual-form-builder/