Vim's documentation lists t_vi as "cursor invisible" and t_ve as "cursor visible", but provides no hints on usage. Naively, I would have guessed that Vim would send the t_vi sequence when you somehow indicated cursor should be hidden (e.g., using something analogous to 'guicursor', or even the 'Cursor' syntax group), but the only way I've been able to hide the cursor in a terminal is to make the "cursor visible" option empty: e.g.,
In other words, telling Vim there's no way to make the cursor visible causes Vim immediately to use the t_vi option value to make it invisible. The seems a little odd and unintuitive to me. I couldn't find any information in Vim's docs on this. Is it well-defined behavior? Can anyone give a better explanation of what's happening here?