added shortcut for toggle mode

browser/main/Detail/MarkdownNoteDetail.js

@@ -55,6 +55,10 @@ class MarkdownNoteDetail extends React.Component {
 
   componentDidMount () {
     ee.on('topbar:togglelockbutton', this.toggleLockButton)
+    ee.on('topbar:togglemodebutton', () => {
+      const reversedType = this.state.editorType === 'SPLIT' ? 'EDITOR_PREVIEW' : 'SPLIT'
+      this.handleSwitchMode(reversedType)
+    })
   }
 
   componentWillReceiveProps (nextProps) {

browser/main/index.js

@@ -9,6 +9,7 @@ import { syncHistoryWithStore } from 'react-router-redux'
 require('./lib/ipcClient')
 require('../lib/customMeta')
 import i18n from 'browser/lib/i18n'
+import ee from 'browser/main/lib/eventEmitter'
 
 const electron = require('electron')
 
@@ -63,6 +64,12 @@ document.addEventListener('keyup', function (e) {
   }
 })
 
+document.addEventListener('keydown', function(e) {
+  if (e.key === 'm' && e.ctrlKey) {
+    ee.emit('topbar:togglemodebutton')
+  }
+});
+
 document.addEventListener('click', function (e) {
   const className = e.target.className
   if (!className && typeof (className) !== 'string') return