I set around 50 of these on the Kanban Plugin and lost them all with either a double click or holding down the click button too long. Not too sure which.
A few days ago i had the exact same issue with the ‘Custom Header Links’ plugin, and decided to post about it as if themes and plugins are making these menus contain large amounts of info they shouldn’t be so easy to accidentally delete due to a poor wifi connection (and partly to vent).