thanks, but unfortunatelly it didn't solve the problem
Any other ideas?
Anyway the problem appears on ipad too, so not just on iphone screens, the not collapsed menu is corrupted also.
I've already tried to restore everything to original state: index.php, template.css, disable every additional plugin, delete all hover, even every style for menu elements, but it still exists. The language switcher plugin's flags also produce the error. Can it be a joomla 3 conflict with the theme?
*UPDATE: even if I change the template, the error exists, so it must be a joomla 3 issue?! I don't think of server config, cause other site runing there doesn't produce the error...
*UPDATE2: clean joomla 3.4.5 install does the same... it's the framework...
But good news that not the template
Thanks for the help