title: Emacs: git-gutter and flycheck conflict makes most keyboard shorcuts broken
body: <p>Sometimes Emacs stops to respond to key bindings, for example:</p>
  
  <ul>
  <li>it's impossible to <code>C-x C-s</code> save buffer</li>
  <li>it's impossible to <code>C y</code> yank killed text</li>
  <li>when mark activated it's invisible</li>
  </ul>
  
  <p>and many other disadvantages.</p>
  
  <p>The only way to return normal behaviour is to relaunch Emacs, though such odd behaviour can occur again very soon. Also, switching buffer to and fro could help a bit, at least it is possible to write buffer.</p>
  
  <p>What is possible reason of this breakage?</p>
  
  <p><em>Remark: Please review. I've tried to simplify question, but if this still is not good enough, let me know and I'll delete it.</em></p>