   isReady: -> document.body? and @container?
 
   show: (html) ->
-    return if @showing or !@isReady()
-    @showing = true
+    return if HelpDialog.showing or !@isReady()
+    HelpDialog.showing = true
     for placeholder, htmlString of html
       @dialogElement.querySelector("#help-dialog-#{placeholder}").innerHTML = htmlString
 
     document.body.appendChild @container
-    @showAdvancedCommands @getShowAdvancedCommands()
+    @showAdvancedCommands(@getShowAdvancedCommands())
 
     # Simulating a click on the help dialog makes it the active element for scrolling.
     DomUtils.simulateClick document.getElementById "vimiumHelpDialog"
 
   hide: ->
-    @showing = false
+    HelpDialog.showing = false
     @container?.parentNode?.removeChild @container
 
   toggle: (html) ->

        false)
      @dialogElement.getElementsByClassName("optionsPage")[0].addEventListener("click", (clickEvent) ->
          clickEvent.preventDefault()
          chrome.runtime.sendMessage {handler: "openOptionsPageInNewTab"}
        false)
      @dialogElement.getElementsByClassName("toggleAdvancedCommands")[0].addEventListener("click",
        HelpDialog.toggleAdvancedCommands, false)

  showing: false

  # This setting is pulled out of local storage. It's false by default.
  getShowAdvancedCommands: -> Settings.get("helpDialog_showAdvancedCommands")

  init: ->
    return if @container?
