When opening the menu editor or selecting a menu item on Safari on MacOS, a confirmation message is briefly visible

Steps to reproduce:

1. use Safari on a Mac or iPad
2. login to the GoGreen CMS
3. edit the English channel
4. click "Edit Menu" next to the main menu
5. select various menu items in the tree, one by one

Expected: no oddities are shown
Actual: each time a new menu item selected, the confirmation dialog is shown and scrolls up immediately