Fix single-doc mode detection

assets/javascripts/app/app.coffee

@@ -145,6 +145,9 @@
                      getComputedStyle(document.querySelector('._header')).backgroundImage isnt 'none'
     catch
 
+  isSingleDoc: ->
+    !!(@DOC or @doc)
+
   isMobile: ->
     # Need to sniff the user agent because some Android and Windows Phone devices don't take
     # resolution (dpi) into account when reporting device width/height.

assets/javascripts/views/content/root_page.coffee

@@ -23,7 +23,7 @@ class app.views.RootPage extends app.View
     return
 
   isHidden: ->
-    app.doc or app.store.get 'hideIntro'
+    app.isSingleDoc() or app.store.get 'hideIntro'
 
   onRoute: ->
 

assets/javascripts/views/layout/document.coffee

@@ -23,7 +23,7 @@ class app.views.Document extends app.View
     app.router.show '/help#shortcuts'
 
   onEscape: ->
-    if app.doc then window.location = '/' else app.router.show '/'
+    if app.isSingleDoc() then window.location = '/' else app.router.show '/'
 
   onBack: ->
     history.back()

assets/javascripts/views/sidebar/doc_list.coffee

@@ -31,7 +31,7 @@ class app.views.DocList extends app.View
 
   render: =>
     @html @tmpl('sidebarDoc', app.docs.all())
-    unless app.doc or app.settings.hasDocs()
+    unless app.isSingleDoc() or app.settings.hasDocs()
       @append @tmpl('sidebarDoc', app.disabledDocs.all(), disabled: true)
     return
 

assets/javascripts/views/sidebar/sidebar.coffee

@@ -16,7 +16,7 @@ class app.views.Sidebar extends app.View
 
     @results = new app.views.Results @search
     @docList = new app.views.DocList
-    @docPicker = new app.views.DocPicker unless app.doc
+    @docPicker = new app.views.DocPicker unless app.isSingleDoc()
 
     app.on 'ready', @showDocList
     $.on document, 'click', @onGlobalClick if @docPicker