thank you Caroline,
in my files the js was called toggle.js and I changed the browserWidth parameters on lines 43 and 54.
the problem is solved, because ipads now use the collapsing menu (= as does the iphone)
however, it would be even better if device detection was used, because small-screen desktops/laptops now also display this menu, which was clearly intended for touchscreen devices.
thanks for this great free template!