Problems in Onepage design / single portfolio / Menu

Problem still:
if i am in onepage design and click to the single portfolio, i cant go back to my mainpage in onepage style without problems. When i click on the #links in mainmenu on single portfolio item, i didn´t come back to mainpage.
If i set the menu buttons with the complete url/#… i indeed come back to the mainpage , but all pictures are no longer displayed. Which alternative i have with menu in single portfolio item and onepage design???

Of course i activated the One-Page option in the theme options already.
Of course I did using the full url (I already wrote that), but then i have got the problem with the pictures!!!

I created a Login to my Website for you, to check out my installation.

http://webab2020.ackermannbau.de/wp-admin

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Regards
Catrin

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