diff --git a/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/left-sidenav/organization-tree.component.spec.ts b/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/left-sidenav/organization-tree.component.spec.ts
index 01b3330d..fda64ea2 100644
--- a/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/left-sidenav/organization-tree.component.spec.ts
+++ b/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/left-sidenav/organization-tree.component.spec.ts
@@ -1,19 +1,19 @@
 import { async, ComponentFixture, TestBed } from '@angular/core/testing';
 
-import { OrganizationComponent } from './organization.component';
+import { OrganizationTreeComponent } from './organization-tree.component';
 
-describe('Chat::LeftSidenav::OrganizationComponent', () => {
-  let component: OrganizationComponent;
-  let fixture: ComponentFixture<OrganizationComponent>;
+describe('Chat::LeftSidenav::OrganizationTreeComponent', () => {
+  let component: OrganizationTreeComponent;
+  let fixture: ComponentFixture<OrganizationTreeComponent>;
 
   beforeEach(async(() => {
     TestBed.configureTestingModule({
-      declarations: [OrganizationComponent]
+      declarations: [OrganizationTreeComponent]
     }).compileComponents();
   }));
 
   beforeEach(() => {
-    fixture = TestBed.createComponent(OrganizationComponent);
+    fixture = TestBed.createComponent(OrganizationTreeComponent);
     component = fixture.componentInstance;
     fixture.detectChanges();
   });
diff --git a/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/main-contents/organization.component.html b/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/main-contents/organization.component.html
index 4635478e..eda1533a 100644
--- a/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/main-contents/organization.component.html
+++ b/projects/ucap-webmessenger-app/src/app/layouts/messenger/components/main-contents/organization.component.html
@@ -18,7 +18,11 @@
             <ng-container *ngIf="!!isSearch">{{
               'common.searchResult' | translate
             }}</ng-container
-            ><span class="text-accent-color person-count"
+            ><span
+              class="text-accent-color person-count"
+              *ngIf="
+                !!departmentUserInfoList && departmentUserInfoList.length > 0
+              "
               >({{ departmentUserInfoList.length
               }}{{ 'common.units.persons' | translate }})</span
             >
@@ -222,7 +226,11 @@
             <li>
               <button
                 mat-flat-button
-                [disabled]="selectedUserList.length > 0 ? 'false' : 'true'"
+                [disabled]="
+                  !!selectedUserList && selectedUserList.length > 0
+                    ? 'false'
+                    : 'true'
+                "
                 (click)="onClickAddGroup()"
                 class="mat-primary"
               >
@@ -232,7 +240,11 @@
             <li>
               <button
                 mat-flat-button
-                [disabled]="selectedUserList.length > 0 ? 'false' : 'true'"
+                [disabled]="
+                  !!selectedUserList && selectedUserList.length > 0
+                    ? 'false'
+                    : 'true'
+                "
                 (click)="onClickChatOpen()"
                 class="mat-primary"
               >
@@ -242,7 +254,11 @@
             <li *ngIf="!!authInfo && authInfo.canVideoConference">
               <button
                 mat-flat-button
-                [disabled]="selectedUserList.length > 0 ? 'false' : 'true'"
+                [disabled]="
+                  !!selectedUserList && selectedUserList.length > 0
+                    ? 'false'
+                    : 'true'
+                "
                 (click)="onClickConference()"
                 class="mat-primary"
               >
@@ -252,7 +268,11 @@
             <li>
               <button
                 mat-flat-button
-                [disabled]="selectedUserList.length > 0 ? 'false' : 'true'"
+                [disabled]="
+                  !!selectedUserList && selectedUserList.length > 0
+                    ? 'false'
+                    : 'true'
+                "
                 (click)="onClickMessage()"
                 class="mat-primary"
               >