diff --git a/.github/CHANGELOG.md b/.github/CHANGELOG.md
index 089e183a..6a26c06f 100644
--- a/.github/CHANGELOG.md
+++ b/.github/CHANGELOG.md
@@ -41,6 +41,7 @@ foo<section>bar</section>zar
 - Add new themes: Ulysses Light, Graphite Light, Material Dark and One Dark.
 - Watch file changed in tabs and show a notice(autoSave is `false`) or update the file(autoSave is `true`)
 - Support input inline Ruby charactors as raw html (#257)
+- Added unsaved tab indicator
 
 **:butterfly:Optimization**
 
@@ -109,6 +110,8 @@ foo<section>bar</section>zar
 - Fixed bug when combine pre list and next list into one when inline update #707
 - Fix renderer error when selection in sidebar (#625)
 - Fixed list parse error [more info](https://github.com/marktext/marktext/issues/831#issuecomment-477719256)
+- Fixed source code mode tab switching
+- Fixed source code mode to preview switching
 
 ### 0.13.65
 
diff --git a/src/main/window.js b/src/main/window.js
index b7d4ad3c..f8719389 100644
--- a/src/main/window.js
+++ b/src/main/window.js
@@ -218,6 +218,7 @@ class AppWindow {
   newTab (win, filePath) {
     this.watcher.watch(win, filePath, 'file')
     loadMarkdownFile(filePath).then(rawDocument => {
+      appMenu.addRecentlyUsedDocument(filePath)
       newTab(win, rawDocument)
     }).catch(err => {
       // TODO: Handle error --> create a end-user error handler.
diff --git a/src/muya/lib/ui/emojis/index.js b/src/muya/lib/ui/emojis/index.js
index 64a9f847..40c4e70b 100644
--- a/src/muya/lib/ui/emojis/index.js
+++ b/src/muya/lib/ui/emojis/index.js
@@ -28,7 +28,7 @@ export const validEmoji = text => {
  */
 
 export const checkEditEmoji = node => {
-  if (node.classList.contains(CLASS_OR_ID['AG_EMOJI_MARKED_TEXT'])) {
+  if (node && node.classList.contains(CLASS_OR_ID['AG_EMOJI_MARKED_TEXT'])) {
     return node
   }
   return false
diff --git a/src/renderer/assets/themes/one-dark.theme.css b/src/renderer/assets/themes/one-dark.theme.css
index 6db787f6..8b373a41 100644
--- a/src/renderer/assets/themes/one-dark.theme.css
+++ b/src/renderer/assets/themes/one-dark.theme.css
@@ -59,6 +59,10 @@
   background: #4d78cc !important;
 }
 
+.drop-container.active {
+  border: 1px dashed #4d78cc !important;
+}
+
 .title-bar .frameless-titlebar-button > div > svg {
   fill: #ffffff;
 }
@@ -84,6 +88,8 @@
 .side-bar-toc .no-data svg {
   fill: #4d78cc !important;
 }
+
+.recent-files-projects a,
 .open-project a {
   color: #9da5b4 !important;
   border: 1px solid #181a1f !important;
@@ -91,6 +97,11 @@
   background-image: linear-gradient(#3a3f4b, #353b45) !important;
   box-shadow: none !important;
 }
+.recent-files-projects a:hover,
+.open-project a:hover {
+  color: #d7dae0 !important;
+  background-image: linear-gradient(#3e4451, #3a3f4b) !important;
+}
 
 .editor-tabs {
   border-bottom: 1px solid #181a1f;
@@ -111,6 +122,9 @@
   height: auto !important;
   background: #4d78cc !important;
 }
+.tabs-container svg.close-icon #unsaved-circle-icon {
+  fill: #4d78cc;
+}
 
 :not(pre) > code[class*="language-"],
 pre.ag-paragraph {
diff --git a/src/renderer/components/editorWithTabs/editor.vue b/src/renderer/components/editorWithTabs/editor.vue
index 2b13898f..c987b2c5 100644
--- a/src/renderer/components/editorWithTabs/editor.vue
+++ b/src/renderer/components/editorWithTabs/editor.vue
@@ -261,7 +261,8 @@
         })
 
         this.editor.on('change', changes => {
-          this.$store.dispatch('LISTEN_FOR_CONTENT_CHANGE', changes)
+          // WORKAROUND: "id: 'muya'"
+          this.$store.dispatch('LISTEN_FOR_CONTENT_CHANGE', Object.assign(changes, { id: 'muya' }))
         })
 
         this.editor.on('format-click', ({ event, formatType, data }) => {
@@ -445,7 +446,7 @@
       },
 
       // listen for `open-single-file` event, it will call this method only when open a new file.
-      setMarkdownToEditor (markdown) {
+      setMarkdownToEditor ({id, markdown}) {
         const { editor } = this
         if (editor) {
           editor.clearHistory()
@@ -455,7 +456,7 @@
       },
 
       // listen for markdown change form source mode or change tabs etc
-      handleMarkdownChange ({ markdown, cursor, renderCursor, history }) {
+      handleMarkdownChange ({ id, markdown, cursor, renderCursor, history }) {
         const { editor } = this
         if (editor) {
           if (history) {
@@ -488,12 +489,15 @@
       bus.$off('undo', this.handleUndo)
       bus.$off('redo', this.handleRedo)
       bus.$off('export', this.handleExport)
+      bus.$off('print-service-clearup', this.handlePrintServiceClearup)
       bus.$off('paragraph', this.handleEditParagraph)
       bus.$off('format', this.handleInlineFormat)
       bus.$off('searchValue', this.handleSearch)
       bus.$off('replaceValue', this.handReplace)
       bus.$off('find', this.handleFind)
-      bus.$off('dotu-select', this.handleSelect)
+      bus.$off('insert-image', this.handleSelect)
+      bus.$off('image-uploaded', this.handleUploadedImage)
+      bus.$off('file-changed', this.handleMarkdownChange)
       bus.$off('editor-blur', this.blurEditor)
       bus.$off('image-auto-path', this.handleImagePath)
       bus.$off('copyAsMarkdown', this.handleCopyPaste)
diff --git a/src/renderer/components/editorWithTabs/sourceCode.vue b/src/renderer/components/editorWithTabs/sourceCode.vue
index 62f952bc..f44e7f0b 100644
--- a/src/renderer/components/editorWithTabs/sourceCode.vue
+++ b/src/renderer/components/editorWithTabs/sourceCode.vue
@@ -26,14 +26,18 @@
 
     computed: {
       ...mapState({
-        'theme': state => state.preferences.theme
+        'theme': state => state.preferences.theme,
+        'currentTab': state => state.editor.currentFile,
       })
     },
 
     data () {
       return {
         contentState: null,
-        editor: null
+        editor: null,
+        commitTimer: null,
+        viewDestroyed: false,
+        tabId: null
       }
     },
 
@@ -48,6 +52,8 @@
 
     created () {
       this.$nextTick(() => {
+        // TODO: Should we load markdown from the tab or mapped vue property?
+        const { id } = this.currentTab
         const { markdown = '', theme, cursor, textDirection } = this
         const container = this.$refs.sourceCode
         const codeMirrorConfig = {
@@ -71,6 +77,7 @@
           codeMirrorConfig.theme = 'one-dark'
         }
         const editor = this.editor = codeMirror(container, codeMirrorConfig)
+
         bus.$on('file-loaded', this.setMarkdown)
         bus.$on('file-changed', this.handleMarkdownChange)
         bus.$on('dotu-select', this.handleSelectDoutu)
@@ -82,13 +89,22 @@
         } else {
           setCursorAtLastLine(editor)
         }
+        this.tabId = id
       })
     },
     beforeDestroy () {
+      // NOTE: Clear timer and manually commit changes. After mode switching and cleanup may follow
+      // further key inputs, so ignore all inputs.
+      this.viewDestroyed = true
+      if (this.commitTimer) clearTimeout(this.commitTimer)
+
       bus.$off('file-loaded', this.setMarkdown)
+      bus.$off('file-changed', this.handleMarkdownChange)
       bus.$off('dotu-select', this.handleSelectDoutu)
-      const { markdown, cursor } = this
-      bus.$emit('file-changed', { markdown, cursor, renderCursor: true })
+
+      const { editor } = this
+      const { cursor, markdown } = this.getMarkdownAndCursor(editor)
+      bus.$emit('file-changed', { id: this.tabId, markdown, cursor, renderCursor: true })
     },
     methods: {
       handleSelectDoutu (url) {
@@ -99,29 +115,37 @@
       },
       listenChange () {
         const { editor } = this
-        let timer = null
-        editor.on('cursorActivity', (cm, event) => {
-          let cursor = cm.getCursor()
-          const markdown = cm.getValue()
+        editor.on('cursorActivity', cm => {
+          const { cursor, markdown } = this.getMarkdownAndCursor(cm)
           const wordCount = getWordCount(markdown)
-          const line = cm.getLine(cursor.line)
-          const preLine = cm.getLine(cursor.line - 1)
-          const nextLine = cm.getLine(cursor.line + 1)
-          cursor = adjustCursor(cursor, preLine, line, nextLine)
-          if (timer) clearTimeout(timer)
-          timer = setTimeout(() => {
-            this.$store.dispatch('LISTEN_FOR_CONTENT_CHANGE', { markdown, wordCount, cursor })
+          if (this.commitTimer) clearTimeout(this.commitTimer)
+          this.commitTimer = setTimeout(() => {
+            // See "beforeDestroy" note
+            if (!this.viewDestroyed) {
+              if (this.tabId) {
+                this.$store.dispatch('LISTEN_FOR_CONTENT_CHANGE', { id: this.tabId, markdown, wordCount, cursor })
+              } else {
+                // This may occur during tab switching but should not occur otherwise.
+                console.warn(`LISTEN_FOR_CONTENT_CHANGE: Cannot commit changes because not tab id was set!`)
+              }
+            }
           }, 1000)
         })
       },
-      setMarkdown (markdown) {
+      // A new file was opened or new tab was added.
+      setMarkdown ({ id, markdown }) {
+        this.prepareTabSwitch()
+
         const { editor } = this
         editor.setValue(markdown)
-        // // NOTE: Don't set the cursor because we load a new file - no tab switch.
+        // NOTE: Don't set the cursor because we load a new file.
         setCursorAtLastLine(editor)
+        this.tabId = id
       },
-      // Only listen to get changes. Do not set history or other things.
-      handleMarkdownChange({ markdown, cursor, renderCursor, history }) {
+      // Another tab was selected - only listen to get changes but don't set history or other things.
+      handleMarkdownChange ({ id, markdown, cursor, renderCursor, history }) {
+        this.prepareTabSwitch()
+
         const { editor } = this
         editor.setValue(markdown)
         // Cursor is null when loading a file or creating a new tab in source code mode.
@@ -130,6 +154,27 @@
         } else {
           setCursorAtLastLine(editor)
         }
+        this.tabId = id
+      },
+      // Get markdown and cursor from CodeMirror.
+      getMarkdownAndCursor (cm) {
+        let cursor = cm.getCursor()
+        const markdown = cm.getValue()
+        const line = cm.getLine(cursor.line)
+        const preLine = cm.getLine(cursor.line - 1)
+        const nextLine = cm.getLine(cursor.line + 1)
+        cursor = adjustCursor(cursor, preLine, line, nextLine)
+        return { cursor, markdown }
+      },
+      // Commit changes from old tab. Problem: tab was already switched, so commit changes with old tab id.
+      prepareTabSwitch () {
+        if (this.commitTimer) clearTimeout(this.commitTimer)
+        if (this.tabId) {
+          const { editor } = this
+          const { cursor, markdown } = this.getMarkdownAndCursor(editor)
+          this.$store.dispatch('LISTEN_FOR_CONTENT_CHANGE', { id: this.tabId, markdown, cursor })
+          this.tabId = null // invalidate tab id
+        }
       }
     }
   }
diff --git a/src/renderer/components/editorWithTabs/tabs.vue b/src/renderer/components/editorWithTabs/tabs.vue
index ed3798ce..1ecee136 100644
--- a/src/renderer/components/editorWithTabs/tabs.vue
+++ b/src/renderer/components/editorWithTabs/tabs.vue
@@ -11,10 +11,11 @@
           @click.stop="selectFile(file)"
         >
           <span>{{ file.filename }}</span>
-          <svg class="icon" aria-hidden="true"
+          <svg class="close-icon icon" aria-hidden="true"
             @click.stop="removeFileInTab(file)"
           >
-            <use xlink:href="#icon-close-small"></use>
+            <circle id="unsaved-circle-icon" cx="6" cy="6" r="3"></circle>
+            <use id="default-close-icon" xlink:href="#icon-close-small"></use>
           </svg>
         </li>
         <li class="new-file">
@@ -49,6 +50,9 @@
 </script>
 
 <style scoped>
+  svg.close-icon #unsaved-circle-icon {
+    fill: var(--themeColor);
+  }
   .editor-tabs {
     width: 100%;
     height: 35px;
@@ -82,6 +86,12 @@
       &:hover > svg {
         opacity: 1;
       }
+      &:hover > svg.close-icon #default-close-icon {
+        display: block !important;
+      }
+      &:hover > svg.close-icon #unsaved-circle-icon {
+        display: none !important;
+      }
       & > span {
         overflow: hidden;
         text-overflow: ellipsis;
@@ -89,6 +99,17 @@
         margin-right: 3px;
       }
     }
+    & > li.unsaved:not(.active) {
+      & > svg.close-icon {
+        opacity: 1;
+      }
+      & > svg.close-icon #unsaved-circle-icon {
+        display: block;
+      }
+      & > svg.close-icon #default-close-icon {
+        display: none;
+      }
+    }
     & > li.active {
       background: var(--itemBgColor);
       &:not(:last-child):after {
@@ -103,6 +124,9 @@
       & > svg {
         opacity: 1;
       }
+      & > svg.close-icon #unsaved-circle-icon {
+        display: none;
+      }
     }
 
     & > li.new-file {
diff --git a/src/renderer/store/editor.js b/src/renderer/store/editor.js
index 1d29a806..23955ec5 100644
--- a/src/renderer/store/editor.js
+++ b/src/renderer/store/editor.js
@@ -25,11 +25,11 @@ const mutations = {
   SET_CURRENT_FILE (state, currentFile) {
     const oldCurrentFile = state.currentFile
     if (!oldCurrentFile.id || oldCurrentFile.id !== currentFile.id) {
-      const { markdown, cursor, history, pathname } = currentFile
+      const { id, markdown, cursor, history, pathname } = currentFile
       window.DIRNAME = pathname ? path.dirname(pathname) : ''
       // set state first, then emit file changed event
       state.currentFile = currentFile
-      bus.$emit('file-changed', { markdown, cursor, renderCursor: true, history })
+      bus.$emit('file-changed', { id, markdown, cursor, renderCursor: true, history })
     }
   },
   ADD_FILE_TO_TABS (state, currentFile) {
@@ -41,12 +41,12 @@ const mutations = {
     tabs.splice(index, 1)
     state.tabs = tabs
     if (file.id === currentFile.id) {
-      const fileState = state.tabs[index] || state.tabs[index - 1] || {}
+      const fileState = state.tabs[index] || state.tabs[index - 1] || state.tabs[0] || {}
       state.currentFile = fileState
       if (typeof fileState.markdown === 'string') {
-        const { markdown, cursor, history, pathname } = fileState
+        const { id, markdown, cursor, history, pathname } = fileState
         window.DIRNAME = pathname ? path.dirname(pathname) : ''
-        bus.$emit('file-changed', { markdown, cursor, renderCursor: true, history })
+        bus.$emit('file-changed', { id, markdown, cursor, renderCursor: true, history })
       }
     }
   },
@@ -55,7 +55,7 @@ const mutations = {
     const { data, pathname } = change
     const { isMixedLineEndings, lineEnding, adjustLineEndingOnSave, isUtf8BomEncoded, markdown, textDirection, filename } = data
     const options = { isUtf8BomEncoded, lineEnding, adjustLineEndingOnSave, textDirection }
-    const fileState = getSingleFileState({ markdown, filename, pathname, options })
+    const newFileState = getSingleFileState({ markdown, filename, pathname, options })
     if (isMixedLineEndings) {
       notice.notify({
         title: 'Line Ending',
@@ -65,18 +65,26 @@ const mutations = {
         showConfirm: false
       }) 
     }
+
+    let fileState = null
     for (const tab of tabs) {
       if (tab.pathname === pathname) {
-        Object.assign(tab, fileState)
+        const oldId = tab.id
+        Object.assign(tab, newFileState)
+        tab.id = oldId
+        fileState = tab
         break
       }
     }
-    state.tabs = tabs
+
+    if (!fileState) {
+      throw new Error('LOAD_CHANGE: Cannot find tab in tab list.')
+    }
+
     if (pathname === currentFile.pathname) {
-      Object.assign(currentFile, fileState)
-      state.currentFile = currentFile
-      const { cursor, history } = currentFile
-      bus.$emit('file-changed', { markdown, cursor, renderCursor: true, history })
+      state.currentFile = fileState
+      const { id, cursor, history } = fileState
+      bus.$emit('file-changed', { id, markdown, cursor, renderCursor: true, history })
     }
   },
   SET_PATHNAME (state, file) {
@@ -139,6 +147,7 @@ const mutations = {
     }
   },
   CLOSE_TABS (state, arr) {
+    let tabIndex = 0
     arr.forEach(id => {
       const index = state.tabs.findIndex(f => f.id === id)
       const { pathname } = state.tabs.find(f => f.id === id)
@@ -151,14 +160,17 @@ const mutations = {
       if (state.currentFile.id === id) {
         state.currentFile = {}
         window.DIRNAME = ''
+        if (arr.length === 1) {
+          tabIndex = index
+        }
       }
     })
     if (!state.currentFile.id && state.tabs.length) {
-      state.currentFile = state.tabs[0]
+      state.currentFile = state.tabs[tabIndex] || state.tabs[tabIndex - 1] || state.tabs[0] || {}
       if (typeof state.currentFile.markdown === 'string') {
-        const { markdown, cursor, history, pathname } = state.currentFile
+        const { id, markdown, cursor, history, pathname } = state.currentFile
         window.DIRNAME = pathname ? path.dirname(pathname) : ''
-        bus.$emit('file-changed', { markdown, cursor, renderCursor: true, history })
+        bus.$emit('file-changed', { id, markdown, cursor, renderCursor: true, history })
       }
     }
   },
@@ -383,11 +395,12 @@ const actions = {
   LISTEN_FOR_OPEN_SINGLE_FILE ({ commit, state, dispatch }) {
     ipcRenderer.on('AGANI::open-single-file', (e, { markdown, filename, pathname, options }) => {
       const fileState = getSingleFileState({ markdown, filename, pathname, options })
+      const { id } = fileState
       const { lineEnding } = options
       commit('SET_GLOBAL_LINE_ENDING', lineEnding)
       dispatch('INIT_STATUS', true)
       dispatch('UPDATE_CURRENT_FILE', fileState)
-      bus.$emit('file-loaded', markdown)
+      bus.$emit('file-loaded', { id, markdown })
       commit('SET_LAYOUT', {
         rightColumn: 'files',
         showSideBar: false,
@@ -424,12 +437,11 @@ const actions = {
 
   NEW_BLANK_FILE ({ commit, state, dispatch }) {
     dispatch('SHOW_TAB_VIEW', false)
-
     const { tabs, lineEnding } = state
     const fileState = getBlankFileState(tabs, lineEnding)
-    const { markdown } = fileState
+    const { id, markdown } = fileState
     dispatch('UPDATE_CURRENT_FILE', fileState)
-    bus.$emit('file-loaded', markdown)
+    bus.$emit('file-loaded', { id, markdown })
   },
 
   /**
@@ -449,8 +461,9 @@ const actions = {
 
     const { markdown, isMixedLineEndings } = markdownDocument
     const docState = createDocumentState(markdownDocument)
+    const { id } = docState
     dispatch('UPDATE_CURRENT_FILE', docState)
-    bus.$emit('file-loaded', markdown)
+    bus.$emit('file-loaded', { id, markdown })
 
     if (isMixedLineEndings) {
       const { filename, lineEnding } = markdownDocument
@@ -476,11 +489,11 @@ const actions = {
     ipcRenderer.on('AGANI::open-blank-window', (e, { lineEnding, markdown: source }) => {
       const { tabs } = state
       const fileState = getBlankFileState(tabs, lineEnding, source)
-      const { markdown } = fileState
+      const { id, markdown } = fileState
       commit('SET_GLOBAL_LINE_ENDING', lineEnding)
       dispatch('INIT_STATUS', true)
       dispatch('UPDATE_CURRENT_FILE', fileState)
-      bus.$emit('file-loaded', markdown)
+      bus.$emit('file-loaded', { id, markdown })
       commit('SET_LAYOUT', {
         rightColumn: 'files',
         showSideBar: false,
@@ -490,24 +503,34 @@ const actions = {
     })
   },
 
-  // LISTEN_FOR_FILE_CHANGE ({ commit, state }) {
-  //   ipcRenderer.on('AGANI::file-change', (e, { file, filename, pathname }) => {
-  //     const { windowActive } = state
-  //     commit('SET_FILENAME', filename)
-  //     commit('SET_PATHNAME', pathname)
-  //     commit('SET_MARKDOWN', file)
-  //     commit('SET_SAVE_STATUS', true)
-  //     if (!windowActive) {
-  //       bus.$emit('file-loaded', file)
-  //     }
-  //   })
-  // },
-
   // Content change from realtime preview editor and source code editor
-  LISTEN_FOR_CONTENT_CHANGE ({ commit, state, rootState }, { markdown, wordCount, cursor, history, toc }) {
+  // WORKAROUND: id is "muya" if changes come from muya and not source code editor! So we don't have to apply the workaround.
+  LISTEN_FOR_CONTENT_CHANGE ({ commit, state, rootState }, { id, markdown, wordCount, cursor, history, toc }) {
     const { autoSave } = rootState.preferences
     const { projectTree } = rootState.project
-    const { pathname, markdown: oldMarkdown, id } = state.currentFile
+    const { id: currentId, pathname, markdown: oldMarkdown } = state.currentFile
+
+    if (!id) {
+      throw new Error(`Listen for document change but id was not set!`)
+    } else if (!currentId || state.tabs.length === 0) {
+      // Discard changes - this case should normally not occur.
+      return
+    } else if (id !== 'muya' && currentId !== id) {
+      // WORKAROUND: We commit changes after switching the tab in source code mode.
+      // Update old tab or discard changes
+      for (const tab of state.tabs) {
+        if (tab.id && tab.id === id) {
+          tab.markdown = markdown
+          // set cursor
+          if (cursor) tab.cursor = cursor
+          // set history
+          if (history) tab.history = history
+          break
+        }
+      }
+      return
+    }
+
     const options = getOptionsFromState(state.currentFile)
     commit('SET_MARKDOWN', markdown)
 
@@ -531,7 +554,7 @@ const actions = {
         commit('UPDATE_PROJECT_CONTENT', { markdown, pathname })
       }
       if (pathname && autoSave) {
-        ipcRenderer.send('AGANI::response-file-save', { id, pathname, markdown, options })
+        ipcRenderer.send('AGANI::response-file-save', { id: currentId, pathname, markdown, options })
       } else {
         commit('SET_SAVE_STATUS', false)
       }