diff --git a/addon/chrome/content/overlay.xul b/addon/chrome/content/overlay.xul
index 46e4d5b..0aaceeb 100644
--- a/addon/chrome/content/overlay.xul
+++ b/addon/chrome/content/overlay.xul
@@ -6,6 +6,6 @@
     <script src="chrome://__addonRef__/content/scripts/index.js" />
     <popup id="zotero-itemmenu">
         <menuseparator />
-        <menuitem id="zotero-itemmenu-__addonRef__-setMainKnowledge" label="&zotero.__addonRef__.itemmenu.setMainKnowledge.label;" oncommand="Zotero.Knowledge4Zotero.events.onEditorEvent({'setMainKnowledge', {editorInstance: }})" class="menuitem-iconic" style="list-style-image: url('chrome://__addonRef__/skin/favicon.png');" />
+        <menuitem id="zotero-itemmenu-__addonRef__-setMainKnowledge" label="&zotero.__addonRef__.itemmenu.setMainKnowledge.label;" oncommand="Zotero.Knowledge4Zotero.events.onEditorEvent.bind(Zotero.Knowledge4Zotero.events)({type: 'setMainKnowledge', content: {params: ZoteroPane.getSelectedItems()[0].id}})" class="menuitem-iconic" style="list-style-image: url('chrome://__addonRef__/skin/favicon.png');" />
     </popup>
 </overlay>
\ No newline at end of file
diff --git a/addon/chrome/locale/en-US/overlay.dtd b/addon/chrome/locale/en-US/overlay.dtd
index f2d4bcf..5315648 100644
--- a/addon/chrome/locale/en-US/overlay.dtd
+++ b/addon/chrome/locale/en-US/overlay.dtd
@@ -1,4 +1,5 @@
 <!ENTITY zotero.__addonRef__.workspace.title "Knowledge Workspace">
+<!ENTITY zotero.__addonRef__.itemmenu.setMainKnowledge.label "Set Main Knowledge">
 
 <!ENTITY zotero.__addonRef__.help.feedback.caption.label "User Guide and Feedback">
 <!ENTITY zotero.__addonRef__.help.feedback.label "GitHub">
diff --git a/addon/chrome/locale/zh-CN/overlay.dtd b/addon/chrome/locale/zh-CN/overlay.dtd
index 6c8354b..d970d59 100644
--- a/addon/chrome/locale/zh-CN/overlay.dtd
+++ b/addon/chrome/locale/zh-CN/overlay.dtd
@@ -1,4 +1,5 @@
 <!ENTITY zotero.__addonRef__.workspace.title "Knowledge工作区">
+<!ENTITY zotero.__addonRef__.itemmenu.setMainKnowledge.label "设置为主Knowledge">
 
 <!ENTITY zotero.__addonRef__.help.feedback.caption.label "User Guide and Feedback">
 <!ENTITY zotero.__addonRef__.help.feedback.label "GitHub">
diff --git a/src/events.ts b/src/events.ts
index 21e96e2..6508af6 100644
--- a/src/events.ts
+++ b/src/events.ts
@@ -151,34 +151,6 @@ class AddonEvents extends AddonBase {
           "closePreview"
         );
       }
-    } else if (message.type === "leaveWorkspace") {
-      /*
-        message.content = {
-          editorInstance,
-          params: "main" | "preview"
-        }
-      */
-      const _window = message.content.editorInstance._iframeWindow;
-      if (message.content.params === "main") {
-        // This is a main knowledge, show all buttons and remove title
-        const title = _window.document.getElementById("knowledge-addlink");
-        this._Addon.views.changeEditorButtonView(
-          title,
-          "mainTitle",
-          "Add Note Link to Knowledge Workspace",
-          "addToKnowledge"
-        );
-        title.setAttribute("class", "");
-        title.setAttribute("style", "font-size: medium");
-      } else {
-        // This is a preview knowledge, show openWorkspace button add hide close botton
-        this._Addon.views.changeEditorButtonView(
-          _window.document.getElementById("knowledge-end"),
-          "export",
-          "Export Markdown with linked Notes",
-          "export"
-        );
-      }
     } else if (message.type === "addToKnowledge") {
       /*
         message.content = {
@@ -194,45 +166,48 @@ class AddonEvents extends AddonBase {
     } else if (message.type === "setMainKnowledge") {
       /*
         message.content = {
-          editorInstance
+          params: itemID
         }
       */
       Zotero.debug("Knowledge4Zotero: setMainKnowledge");
       let mainKnowledgeID = parseInt(
         Zotero.Prefs.get("Knowledge4Zotero.mainKnowledgeID")
       );
-      if (message.content.editorInstance._item.id !== mainKnowledgeID) {
+      let itemID = message.content.params;
+      if (itemID === mainKnowledgeID) {
+        this._Addon.views.showProgressWindow(
+          "Knowledge",
+          "Already a main Knowledge."
+        );
+      } else if (!Zotero.Items.get(itemID).isNote()) {
+        this._Addon.views.showProgressWindow(
+          "Knowledge",
+          "Not a valid note item."
+        );
+      } else {
         if (Zotero.Prefs.get("Knowledge4Zotero.mainKnowledgeID")) {
           let confirmChange = confirm(
-            "Will remove current Knowledge Workspace. Confirm?"
+            "Will change current Knowledge Workspace. Confirm?"
           );
           if (!confirmChange) {
             return;
           }
         }
-        Zotero.Prefs.set(
-          "Knowledge4Zotero.mainKnowledgeID",
-          message.content.editorInstance._item.id
-        );
-        // Set the button to selected state
-        this._Addon.views.changeEditorButtonView(
-          message.content.event.target,
-          "isMainKnowledge",
-          "Edit the main knowledge in Workspace"
-        );
+        Zotero.Prefs.set("Knowledge4Zotero.mainKnowledgeID", itemID);
         await this._Addon.knowledge.setWorkspaceNote("main");
         for (let editor of Zotero.Notes._editorInstances) {
           await editor._initPromise;
-          if (editor._item.id === mainKnowledgeID) {
-            let button =
-              editor._iframeWindow.document.getElementById("knowledge-start");
-            if (button) {
-              this._Addon.views.changeEditorButtonView(
-                button,
-                "notMainKnowledge",
-                "Open Workspace"
-              );
-            }
+          let isMainKnowledge = editor._item.id === mainKnowledgeID;
+          let button =
+            editor._iframeWindow.document.getElementById("knowledge-start");
+          if (button) {
+            this._Addon.views.changeEditorButtonView(
+              button,
+              isMainKnowledge ? "isMainKnowledge" : "notMainKnowledge",
+              isMainKnowledge
+                ? "Edit the main knowledge in Workspace"
+                : "Open Workspace"
+            );
           }
         }
       }
diff --git a/src/knowledge.ts b/src/knowledge.ts
index f1cae41..13dbe0d 100644
--- a/src/knowledge.ts
+++ b/src/knowledge.ts
@@ -60,6 +60,18 @@ class Knowledge extends AddonBase {
     return _window.document.getElementById(`zotero-note-editor-${type}`);
   }
 
+  async getWorkspaceEditorInstance(
+    type: "main" | "preview" = "main"
+  ): Promise<EditorInstance> {
+    let noteEditor = (await this.getWorkspaceEditor(type)) as any;
+    let t = 0;
+    while (!noteEditor.getCurrentInstance() && t < 500) {
+      t += 1;
+      await Zotero.Promise.delay(10);
+    }
+    return noteEditor.getCurrentInstance() as EditorInstance;
+  }
+
   async setWorkspaceNote(
     type: "main" | "preview" = "main",
     note: ZoteroItem = undefined
@@ -76,15 +88,6 @@ class Knowledge extends AddonBase {
     }
     await this.waitWorkspaceReady();
     let noteEditor: any = await this.getWorkspaceEditor(type);
-    let lastEditorInstance = noteEditor.getCurrentInstance() as EditorInstance;
-    if (lastEditorInstance) {
-      await this._Addon.events.onEditorEvent(
-        new EditorMessage("leaveWorkspace", {
-          editorInstance: lastEditorInstance,
-          params: type,
-        })
-      );
-    }
     noteEditor.mode = "edit";
     noteEditor.viewMode = "library";
     noteEditor.parent = null;