The alt-v command toggles the vim editing mode.

Pressing alt-v will toggle between the vim and basic editing modes for the text editor.

VHV starts out with the basic editor, as indicated by the yellowish background to the text editor:

basic editing mode
basic editing mode (indicated by the yellow color of the text editor).

Typing alt-v will toggle the editor to and from vim mode. When in vim mode, the text editor has a dark blue background:

vim editing mode
vim editing mode (indicated by the dark blue color of the text editor).

Typing alt-v while in vim editing mode will return to basic editing mode.