Hm, I feel stupid. Read the FAQ, you idiot (meaning myself)!
So this is solved, just uncheck one box.
Solved! After some further investigation I found out that the footer.php caused this issue. So I deleted the Divi-Child footer.php and corrected the Divi footer.php. And now the WP Store Locator is working fine. Thank you Tijmen, for showing me the direction for the solution.
Thanks for the reply, Tijmen. Unfortunately I don’t have any knowledge about CSS (that’s why I try to use WP with ready to use themes), but I did place the WPSL almost at the top of the testsite, without any better results. Hm!
BTW, here is the test website:
http://shivatnatural.nl/testshivat/
The store locator is for the moment located at the bottom.