GS Evolve Theme

[asemion]

unfortunately this workaround didnt work, now i've again Kontakt and Contact as menu-entry and also 1x kontakt and 2x contact in the pages tab (kontakt=menu-entry, contact=menu-entry, contact=no menu-entry)



could it be that this is a GS topic and not an issue of your template? if yes, do you have any clue where i should start searching...

This is due to the fact that you have changed the page field "Custom URL (Slug)" value. For this reason, the GS most likely create an additional page file.
Correction options may be two:

1. If your site will be used only one language (German) then you must have only one contact form page file and opened it for editing to change only two fields - "Page Title" and "Menu Text" (do not change page "Slug" field).
   
2. If you are planning to have a multilingual website then you have to create and translate separate pages for each language. Also yet to be installed and set of the i18n plugin.
   

I hope this information will help you.
Andrejus.