Ctrl + <non-ascii-key> gets mapped on vim but not on gvim

Binary package hint: vim

The sequence CTRL + <non-ascii-key> only works on Vim (with langmap converting it to CTRL + <ascii-key>). On Gvim, the CTRL key seems to be ignored and langmap is applied just to <non-ascii-key>.

For example, if langmap includes the mapping "к;r", then ^к should behave like ^r (which is what happens in Vim), but when ^к is pressed in Gvim, it is as if just к had been pressed (which langmap converts to r).

I also tried mapping <C-к>, but the mapping doesn't seem to ever get activated, and <C-к> still behaves like just к.

Ubuntu version: 10.10.

$ vim --version
VIM - Vi IMproved 7.2 (2008 Aug 9, compiled Sep 28 2010 11:02:36)
Included patches: 1-330
Compiled by buildd@
Huge version with GTK2-GNOME GUI. [...]