When you customize the toolbar (Explicitly, Settings -> Configure Toolbars -> Math), the menus on top dissapear or change. Setting losses some submenus (Explicitly, the Configure ones). This have been an issue for a long time (a year at least) and it has not been repared yet. I use Linux Mint (KDE) 17.10
Hi there, I can also confirm this. Looks like a duplicate of bug 314580.
Indeed. *** This bug has been marked as a duplicate of bug 314580 ***