Uncaught Error: class 'Undo' not found

[directrix1]

1. type something in
2. get out of edit mode
3. hit 'u'

Atom: 1.45.0 x64
Electron: 4.2.7
OS: Linux Mint
Thrown From: vim-mode-plus package 1.36.4

Stack Trace

Uncaught Error: class 'Undo' not found

At /home/dtx/.atom/packages/vim-mode-plus/lib/operation-stack.js:164

Error: class 'Undo' not found
    at Function.getClass (/packages/vim-mode-plus/lib/base.js:218:13)
    at OperationStack.run (/packages/vim-mode-plus/lib/operation-stack.js:87:24)
    at /packages/vim-mode-plus/lib/vim-state.js:70:33)
    at CommandRegistry.handleCommandEvent (/usr/share/atom/resources/app/static/<embedded>:11:349290)
    at KeymapManager.dispatchCommandEvent (/usr/share/atom/resources/app/static/<embedded>:11:1254747)
    at KeymapManager.handleKeyboardEvent (/usr/share/atom/resources/app/static/<embedded>:11:1250881)
    at WindowEventHandler.handleDocumentKeyEvent (/usr/share/atom/resources/app/static/<embedded>:11:284496)

Commands

  5x -4:01.6.0 core:backspace (input.hidden-input)
 14x -3:59.9.0 blur (input.hidden-input)
     -0:09.0 vim-mode-plus:insert-after (input.hidden-input)
     -0:08.6.0 editor:newline (input.hidden-input)
     -0:08.0 vim-mode-plus:activate-normal-mode (input.hidden-input)
     -0:07.0 vim-mode-plus:undo (input.hidden-input)
  2x -0:00.0 blur (input.hidden-input)

Non-Core Packages

clipboard-plus 0.5.1 
ex-mode 0.18.0 
git-plus 8.7.1 
vim-mode-clipboard-plus 0.3.0 
vim-mode-plus 1.36.4 
vim-mode-plus-macros 0.1.2