Hi, I have been noticed, that (on an iphone) if you touch the offcanvas menu items with a submenu, the offcanvas menu disappears and becomes all white. I'm not sure, it happens always and with both menu items with a submenu. (View images) Here is a video, where you can see what happens: https://www.jochenwenz.com/images/off-canvas.mp4
Thanks for helping!
Hi 1omegazip, You can use the following CSS code to resolve the issue:
.t4-offcanvas .t4-off-canvas-body .navbar.drilldown-effect .navbar-nav .dropdown-menu.show { display: block !important; }
Thank you dominic, it seems to work perfectly now