Classic Menu Indicator shows zombie applications and folders

Classic Menu Indicator shows applications that have long been uninstalled. These entries are not shown in the gnome menu editor. So, I can not remove them. It also displays some duplicate folders with zombie entries which I can not get rid of.
Details:
Menu "Internet" shows entrie "ixconn-Konfiguration" (see attached png top left). But not such entry is shown in the gnome menu editor (see attached png bottom left) (ixconn has once been installed on this computer, but has been uninstalled long ago.)
Main Menu shows duplicate folder entries "Systemwerkzeuge" (system tools) and "Zubehör" (accessories) below "Ubuntu Software Center" both containing an entry "Dolphin" (see attached png top middle). In the gnome menu editor these duplicate folders are emtpy (see attached png bottom middle) (Dolphin has once been installed on this computer, but has been uninstalled long ago.)
These duplicate folder entries are synchronized with the original ones. That is, if in the gnome menu editor the "display" checkbox is checked or unchecked for the original entry, the chekcbox for the duplicate entry behaves likewise (see attached png right top and bottom). Deleting the duplicate folders in gnome menu editor is noneffective. They are still being displayed in Classic Menu Indicator and are shown again when menu editor is reopened.