diff --git a/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/left-nav.component.ts b/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/left-nav.component.ts
index ce1b693b..f5186c01 100644
--- a/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/left-nav.component.ts
+++ b/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/left-nav.component.ts
@@ -1,7 +1,7 @@
 import { Component, OnInit, OnDestroy, Inject } from '@angular/core';
 import { NGXLogger } from 'ngx-logger';
 import { ucapAnimations } from '@ucap-webmessenger/ui';
-import { Observable, Subscribable, Subscription } from 'rxjs';
+import { Observable, Subscribable, Subscription, timer } from 'rxjs';
 import { Store, select } from '@ngrx/store';
 
 import * as AppStore from '@app/store';
@@ -9,7 +9,7 @@ import * as MessageStore from '@app/store/messenger/message';
 import * as SettingsStore from '@app/store/messenger/settings';
 import { MatTabChangeEvent } from '@angular/material/tabs';
 import { MainMenu } from '@app/types';
-import { tap, map } from 'rxjs/operators';
+import { tap, map, debounce } from 'rxjs/operators';
 import { UCAP_NATIVE_SERVICE, NativeService } from '@ucap-webmessenger/native';
 
 @Component({
@@ -69,6 +69,7 @@ export class LeftNaviComponent implements OnInit, OnDestroy {
 
     this.gnbMenuIndexSubscription = this.store
       .pipe(select(AppStore.MessengerSelector.SettingsSelector.gnbMenuIndex))
+      .pipe(debounce(() => timer(300)))
       .subscribe(index => {
         switch (index) {
           case MainMenu.Group:
diff --git a/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/main-contents.component.html b/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/main-contents.component.html
index 2b871b0e..13b680d5 100644
--- a/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/main-contents.component.html
+++ b/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/main-contents.component.html
@@ -5,13 +5,13 @@
 ></app-layout-messenger-intro>
 
 <app-layout-messenger-messages
-  *ngIf="
-    !!this.selectedChat &&
-    (this.gnbMenuIndex$ | async) !== MainMenu.Organization
-  "
+  *ngIf="!!this.selectedChat"
   (openProfile)="onClickOpenProfile($event)"
   (closeRightDrawer)="onCloseRightDrawer()"
   (sendCall)="onClickSendClickToCall($event)"
+  [style.display]="
+    MainMenu.Organization !== (this.gnbMenuIndex$ | async) ? 'flex' : 'none'
+  "
 ></app-layout-messenger-messages>
 <!-- 아래와 같이 display 효과를 쓰려면 block 대산 flex 사용. (화면 전환이 매끄럽지만 스크롤이 그대로인 문제 있음.) -->
 <app-layout-messenger-organization