diff --git a/background/background.js b/background/background.js
index 8fa4b8e0..6d15e8d4 100644
--- a/background/background.js
+++ b/background/background.js
@@ -19,6 +19,7 @@ window.API_METHODS = Object.assign(window.API_METHODS || {}, {
   importStyle: styleManager.importStyle,
   styleExists: styleManager.styleExists,
   getStyle: styleManager.get,
+  getAllStyles: styleManager.getAllStyles, // used by importer
 
   getTabUrlPrefix() {
     return this.sender.tab.url.match(/^([\w-]+:\/+[^/#]+)/)[1];
diff --git a/background/style-manager.js b/background/style-manager.js
index 28026482..a276c911 100644
--- a/background/style-manager.js
+++ b/background/style-manager.js
@@ -56,8 +56,12 @@ const styleManager = (() => {
         port = null;
         if (id) {
           const style = styles.get(id);
+          if (!style) {
+            // maybe deleted
+            return;
+          }
           style.preview = null;
-          broadcastStyleUpdated(style.data, 'editPreview');
+          broadcastStyleUpdated(style.data, 'editPreviewEnd');
         }
       });
     });
@@ -128,7 +132,7 @@ const styleManager = (() => {
   function importStyle(data) {
     // FIXME: is it a good idea to save the data directly?
     return saveStyle(data)
-      .then(newData => handleSave(newData));
+      .then(newData => handleSave(newData, 'import'));
   }
 
   function installStyle(data) {
diff --git a/manage/import-export.js b/manage/import-export.js
index d15cd409..dc94f9ed 100644
--- a/manage/import-export.js
+++ b/manage/import-export.js
@@ -56,19 +56,14 @@ function importFromFile({fileTypeFilter, file} = {}) {
 }
 
 
-function importFromString(jsonString, oldStyles) {
-  if (!oldStyles) {
-    return API.getStylesInfo().then(styles => importFromString(jsonString, styles));
-  }
+function importFromString(jsonString) {
   const json = tryJSONparse(jsonString);
   if (!Array.isArray(json)) {
     return Promise.reject(new Error('the backup is not a valid JSON file'));
   }
-  const oldStylesById = new Map(
-    oldStyles.map(style => [style.id, style]));
-  const oldStylesByName = json.length && new Map(
-    oldStyles.map(style => [style.name.trim(), style]));
-
+  let oldStyles;
+  let oldStylesById;
+  let oldStylesByName;
   const stats = {
     added:       {names: [], ids: [], legend: 'importReportLegendAdded'},
     unchanged:   {names: [], ids: [], legend: 'importReportLegendIdentical'},
@@ -78,27 +73,25 @@ function importFromString(jsonString, oldStyles) {
     invalid:     {names: [], legend: 'importReportLegendInvalid'},
   };
 
-  let index = 0;
-  let lastRenderTime = performance.now();
-  const renderQueue = [];
-  const RENDER_NAP_TIME_MAX = 1000; // ms
-  const RENDER_QUEUE_MAX = 50; // number of styles
-  return proceed();
-
-  function proceed() {
-    while (index < json.length) {
-      const item = json[index++];
-      const info = analyze(item);
-      if (!info) {
-        continue;
+  return API.getAllStyles().then(styles => {
+    // make a copy of the current database, that may be used when we want to
+    // undo
+    oldStyles = styles;
+    oldStylesById = new Map(
+      oldStyles.map(style => [style.id, style]));
+    oldStylesByName = json.length && new Map(
+      oldStyles.map(style => [style.name.trim(), style]));
+    return Promise.all(json.map((item, i) => {
+      const info = analyze(item, i);
+      if (info) {
+        return API.importStyle(item)
+          .then(style => updateStats(style, info));
       }
-      return API.importStyle(item)
-        .then(style => account({style, info}));
-    }
-    return done();
-  }
+    }));
+  })
+    .then(done);
 
-  function analyze(item) {
+  function analyze(item, index) {
     if (typeof item !== 'object' ||
         !item ||
         !item.name ||
@@ -142,18 +135,6 @@ function importFromString(jsonString, oldStyles) {
         .some(field => oldStyle[field] && oldStyle[field] === newStyle[field]);
   }
 
-  function account({style, info}) {
-    renderQueue.push(style);
-    if (performance.now() - lastRenderTime > RENDER_NAP_TIME_MAX
-    || renderQueue.length > RENDER_QUEUE_MAX) {
-      setTimeout(scrollElementIntoView, 0, $('#style-' + renderQueue.pop().id));
-      renderQueue.length = 0;
-      lastRenderTime = performance.now();
-    }
-    updateStats(style, info);
-    return proceed();
-  }
-
   function updateStats(style, {oldStyle, metaEqual, codeEqual}) {
     if (!oldStyle) {
       stats.added.names.push(style.name);
diff --git a/manage/manage.js b/manage/manage.js
index e13c8865..619bd9b0 100644
--- a/manage/manage.js
+++ b/manage/manage.js
@@ -48,7 +48,8 @@ function onRuntimeMessage(msg) {
   switch (msg.method) {
     case 'styleUpdated':
     case 'styleAdded':
-      handleUpdate(msg.style, msg);
+      API.getStylesInfo({id: msg.style.id})
+        .then(([style]) => handleUpdate(style, msg));
       break;
     case 'styleDeleted':
       handleDelete(msg.style.id);
@@ -521,7 +522,7 @@ function handleUpdate(style, {reason, method} = {}) {
   if (reason === 'editPreview') return;
   // the style was toggled and refreshAllTabs() sent a mini-notification,
   // but we've already processed 'styleUpdated' sent directly from notifyAllTabs()
-  if (!style.sections) return;
+  // if (!style.sections) return;
   let entry;
   let oldEntry = $(ENTRY_ID_PREFIX + style.id);
   if (oldEntry && method === 'styleUpdated') {
diff --git a/popup/popup.js b/popup/popup.js
index 6dbc7591..4d253e63 100644
--- a/popup/popup.js
+++ b/popup/popup.js
@@ -25,10 +25,14 @@ getActiveTab()
   )
   .then(url => Promise.all([
     (tabURL = URLS.supported(url) ? url : '') &&
-    API.getStylesInfoByUrl(tabURL),
+      API.getStylesInfoByUrl(tabURL),
     onDOMready().then(initPopup),
   ]))
   .then(([results]) => {
+    if (!results) {
+      // unsupported URL;
+      return;
+    }
     showStyles(results.map(r => Object.assign(r.data, r)));
   })
   .catch(console.error);