diff --git a/CHANGELOG.md b/CHANGELOG.md
index fefb80c..59e2e72 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fix
+
+- Prevent several instances of a sub menu when opening with the mouse
+
 ## [17.0.0] - 2023-11-10
 
 ### BREAKING CHANGES
diff --git a/libs/ngx-contextmenu/src/lib/components/context-menu-content/context-menu-content.component.spec.ts b/libs/ngx-contextmenu/src/lib/components/context-menu-content/context-menu-content.component.spec.ts
index 4f1a1e9..42f69e0 100644
--- a/libs/ngx-contextmenu/src/lib/components/context-menu-content/context-menu-content.component.spec.ts
+++ b/libs/ngx-contextmenu/src/lib/components/context-menu-content/context-menu-content.component.spec.ts
@@ -903,4 +903,49 @@ describe('Component: ContextMenuContentComponent', () => {
       ).not.toHaveBeenCalled();
     });
   });
+
+  describe('#openSubMenu', () => {
+    beforeEach(() => {
+      configureTestingModule();
+      component.contextMenuContentItems = new QueryList();
+    });
+
+    it('should show subMenu', () => {
+      const subMenu =
+        TestBed.createComponent(ContextMenuComponent).componentInstance;
+      const event = new MouseEvent('click');
+
+      spyOn(subMenu, 'show');
+      component.openSubMenu(subMenu, event);
+
+      expect(subMenu.show).toHaveBeenCalledWith({
+        anchoredTo: 'position',
+        x: 0,
+        y: 0,
+        value: undefined,
+      });
+    });
+
+    it('should not show subMenu if already opened', () => {
+      const subMenu =
+        TestBed.createComponent(ContextMenuComponent).componentInstance;
+      const event = new MouseEvent('click');
+      spyOnProperty(subMenu, 'isOpen', 'get').and.returnValue(true);
+      spyOn(subMenu, 'show');
+      component.openSubMenu(subMenu, event);
+
+      expect(subMenu.show).not.toHaveBeenCalled();
+    });
+
+    it('should not throw if subMenu does not exist', () => {
+      const subMenu =
+        TestBed.createComponent(ContextMenuComponent).componentInstance;
+      const event = new MouseEvent('click');
+
+      spyOn(subMenu, 'show');
+      expect(() => {
+        component.openSubMenu(undefined, event);
+      }).not.toThrow();
+    });
+  });
 });
diff --git a/libs/ngx-contextmenu/src/lib/components/context-menu-content/context-menu-content.component.ts b/libs/ngx-contextmenu/src/lib/components/context-menu-content/context-menu-content.component.ts
index 12fc982..e4db2e7 100644
--- a/libs/ngx-contextmenu/src/lib/components/context-menu-content/context-menu-content.component.ts
+++ b/libs/ngx-contextmenu/src/lib/components/context-menu-content/context-menu-content.component.ts
@@ -242,7 +242,7 @@ export class ContextMenuContentComponent<T>
     subMenu: ContextMenuComponent<T> | undefined,
     event: MouseEvent | KeyboardEvent
   ): void {
-    if (!subMenu) {
+    if (!subMenu || subMenu.isOpen) {
       return;
     }