Responsive shown in standard site

[max48308]

Hello,

I have a site in Magix Web Design 11 (but same results with evaluation copy of version 13) where responsive design is worked on parallel to the standard design.

Worked great until now.

Now I created a new page ( as a copy of another one) and all of a sudden the responsive page is shown within the standard page in browser. Only the new created one - not the older pages.

See picture attached.

Any idea?

Thanks for your help.

Max