diff --git a/cfb-web/src/plugins/shortcuts.ts b/cfb-web/src/plugins/shortcuts.ts
index 2d08b95..ce8faf8 100644
--- a/cfb-web/src/plugins/shortcuts.ts
+++ b/cfb-web/src/plugins/shortcuts.ts
@@ -14,7 +14,7 @@ export class WebShortcutsPlugin implements IPlugin {
         if (checkKeys(e, ["control", "z"])) {
           const executer = e.world.getPlugin(ExecuterPlugin);
           if (!executer) {
-            Logger.warn("`undo` failed: `ExecuterPlugin` is not found in the world");
+            Logger.error("`undo` failed: `ExecuterPlugin` is not found in the world");
           } else {
             if (executer.canUndo()) {
               executer.undo();
@@ -23,7 +23,7 @@ export class WebShortcutsPlugin implements IPlugin {
         } else if (checkKeys(e, ["control", "shift", "z"])) {
           const executer = e.world.getPlugin(ExecuterPlugin);
           if (!executer) {
-            Logger.warn("`redo` failed: `ExecuterPlugin` is not found in the world");
+            Logger.error("`redo` failed: `ExecuterPlugin` is not found in the world");
           } else {
             if (executer.canRedo()) {
               executer.redo();
diff --git a/cfb-web/src/plugins/zoom.ts b/cfb-web/src/plugins/zoom.ts
index 034f3c4..cd56e94 100644
--- a/cfb-web/src/plugins/zoom.ts
+++ b/cfb-web/src/plugins/zoom.ts
@@ -1,7 +1,7 @@
 import type { IPlugin } from "@carefree0910/cfb-core";
 import type { WebWorld } from "../world.ts";
 
-import { Point, wheelEvent } from "@carefree0910/cfb-core";
+import { Logger, Point, wheelEvent } from "@carefree0910/cfb-core";
 import { getNormalizedWheelDelta } from "./utils.ts";
 import { WebKeyboardPlugin } from "./keyboard.ts";
 
@@ -10,7 +10,9 @@ export class WebZoomPlugin implements IPlugin {
     wheelEvent.on((e) => {
       const world = e.world as WebWorld;
       const keyboard = world.getPlugin(WebKeyboardPlugin);
-      if (keyboard) {
+      if (!keyboard) {
+        Logger.error("cannot find `keyboard` plugin, `zoom` plugin will not work");
+      } else {
         const status = keyboard.getStatus();
         if (status.ctrlKey || status.metaKey) {
           const deltaY = getNormalizedWheelDelta(e.e, 25).y;