diff --git a/packages/libro-lsp/src/adapters/notebook-adapter.ts b/packages/libro-lsp/src/adapters/notebook-adapter.ts
index 1bf8fdd7..5140813b 100644
--- a/packages/libro-lsp/src/adapters/notebook-adapter.ts
+++ b/packages/libro-lsp/src/adapters/notebook-adapter.ts
@@ -188,7 +188,7 @@ export class NotebookAdapter extends WidgetLSPAdapter<LibroView> {
    * @param _session - Session context of changed kernel
    * @param change - Changed data
    */
-  async onKernelChanged(): Promise<void> {
+  onKernelChanged = async (): Promise<void> => {
     try {
       // note: we need to wait until ready before updating language info
       const oldLanguageInfo = this._languageInfo;
@@ -212,7 +212,7 @@ export class NotebookAdapter extends WidgetLSPAdapter<LibroView> {
       // try to reconnect anyway
       this.reloadConnection();
     }
-  }
+  };
 
   /**
    * Dispose the widget.
@@ -397,9 +397,11 @@ export class NotebookAdapter extends WidgetLSPAdapter<LibroView> {
       return;
     }
 
-    this._activeEditorChanged.fire({
-      editor: this.getCellEditor(libroModel.active)!,
-    });
+    if (libroModel.active) {
+      this._activeEditorChanged.fire({
+        editor: this.getCellEditor(libroModel.active)!,
+      });
+    }
   }
 
   /**
diff --git a/packages/libro-lsp/src/connection-manager.ts b/packages/libro-lsp/src/connection-manager.ts
index fbcadf28..c7f2d0fe 100644
--- a/packages/libro-lsp/src/connection-manager.ts
+++ b/packages/libro-lsp/src/connection-manager.ts
@@ -427,7 +427,7 @@ export class DocumentConnectionManager implements ILSPDocumentConnectionManager
    * language.
    */
   disconnect(languageId: TLanguageServerId): void {
-    this.disconnect(languageId);
+    this.disconnectServer(languageId);
   }
 
   /**
diff --git a/packages/libro-lsp/src/connection.ts b/packages/libro-lsp/src/connection.ts
index 4cd7aede..b939603d 100644
--- a/packages/libro-lsp/src/connection.ts
+++ b/packages/libro-lsp/src/connection.ts
@@ -254,7 +254,9 @@ export class LSPConnection extends LspWsConnection implements ILSPConnection {
     if (this.isDisposed) {
       return;
     }
-    Object.values(this.serverRequests).forEach((request) => request.clearHandler());
+    if (this.serverRequests) {
+      Object.values(this.serverRequests).forEach((request) => request.clearHandler());
+    }
     this.close();
     super.dispose();
   }