THE MENU IN GVim suddenly disappeared?! I did not provoke this by making changes in any .vimrc, .gvimrc or in any files in the .vim directory. The menu was just gone after a boot when GVim auto-loaded the documents open before the reboot. The system is Kubuntu 8.04 and vim-gnome.
I googled for a solution and eventually found an answer at Nabble (thanks goes to mmarko). It appears that something (?) changed the Gnome setup for GVim in the file ~/gnome2/vim.
No menu:
[Placement]
Dock=Toolbar\\0,0,0,0\\Menubar\\0,0,0,0
With menu:
[Placement]
Dock=Toolbar\\0,1,0,0\\Menubar\\0,0,0,0