[Theme: customizr] wrapping of site-logo and menu in theme

Hi,

I admit, this might be a CSS issue.
I am building a web page with the customizr theme (WP unforntunately not online yet).
The site-logo and the menu are supposed to be in one hoirizontal line.
Like here

“All of a sudden”TM I have a wrapping/line break between the logo and the menu.
So the menu starts below the Logo and not right of the logo.

I remove the theme completely and even reinstalled the theme. I removed the logo so that only the blog name will be displayed, but it still persists.

Does anybody know that?

Kind regards
Cornelius