Lexical autocomplete (Ctrl+N/Ctrl+P) works in App.config or regular text file but not in .cs files

[gorcig]

In insert mode some characters of word are written and after the Ctrl+N is pressed in config or text file it provides a list of words starting with the beginning of the word. This doesn't happen to be the case when coding in .cs file.

All keybindings are set to handle with VsVim.

I believe it has to do something with the Intellisense but haven't found solution yet.