diff --git a/examples/vite-demo-vanilla-bundle/src/examples/example12.ts b/examples/vite-demo-vanilla-bundle/src/examples/example12.ts
index 6a87cf77b..3a61e3691 100644
--- a/examples/vite-demo-vanilla-bundle/src/examples/example12.ts
+++ b/examples/vite-demo-vanilla-bundle/src/examples/example12.ts
@@ -986,6 +986,7 @@ export default class Example12 {
         // showResetButtonOnEachEditor: true,
         onClose: () => Promise.resolve(confirm('You have unsaved changes, are you sure you want to close this window?')),
         onError: (error) => alert(error.message),
+        // onRendered: (modalElm) => console.log(modalElm),
         onSave: (formValues, _selection, dataContextOrUpdatedDatasetPreview) => {
           const serverResponseDelay = 50;
 
diff --git a/packages/common/src/interfaces/compositeEditorOpenDetailOption.interface.ts b/packages/common/src/interfaces/compositeEditorOpenDetailOption.interface.ts
index 0add7300c..a92fece39 100644
--- a/packages/common/src/interfaces/compositeEditorOpenDetailOption.interface.ts
+++ b/packages/common/src/interfaces/compositeEditorOpenDetailOption.interface.ts
@@ -107,6 +107,9 @@ export interface CompositeEditorOpenDetailOption {
   /** onError callback allows user to override what the system does when an error (error message & type) is thrown, defaults to console.log */
   onError?: (error: OnErrorOption) => void;
 
+  /** onRendered callback allows the user to optionally execute something after the modal is created and rendered in the DOM (for example add Bootstrap `bs-data-theme="dark"` attribute to the modal element) */
+  onRendered?: (modalElm: HTMLDivElement) => void;
+
   /**
    * onSave callback will be triggered (when defined) after user clicked the save/apply button,
    * this callback is used when connecting a backend server with custom code to execute after clicking the save/apply button
diff --git a/packages/composite-editor-component/src/slick-composite-editor.component.spec.ts b/packages/composite-editor-component/src/slick-composite-editor.component.spec.ts
index 0d80f3b35..cdc0235b5 100644
--- a/packages/composite-editor-component/src/slick-composite-editor.component.spec.ts
+++ b/packages/composite-editor-component/src/slick-composite-editor.component.spec.ts
@@ -569,6 +569,22 @@ describe('CompositeEditorService', () => {
       expect(compositeContainerElm).toBeTruthy();
     });
 
+    it('should execute "onRendered" callback after creating & rendering the composite modal window', () => {
+      const mockProduct = { id: 222, address: { zip: 123456 }, product: { name: 'Product ABC', price: 12.55 } };
+      jest.spyOn(gridStub, 'getDataItem').mockReturnValue(mockProduct);
+      const mockOnRenderedCallback = jest.fn();
+
+      component = new SlickCompositeEditorComponent();
+      component.init(gridStub, container);
+      component.openDetails({ headerTitle: 'Details', onRendered: mockOnRenderedCallback });
+      const compositeContainerElm = document.querySelector('div.slick-editor-modal.slickgrid_123456') as HTMLSelectElement;
+
+      expect(mockOnRenderedCallback).toHaveBeenCalledWith(expect.any(HTMLDivElement));
+      expect(component).toBeTruthy();
+      expect(component.constructor).toBeDefined();
+      expect(compositeContainerElm).toBeTruthy();
+    });
+
     it('should execute "onClose" callback when user confirms the closing of the modal when "onClose" callback is defined', (done) => {
       const mockProduct = { id: 222, address: { zip: 123456 }, productName: 'Product ABC', price: 12.55, field2: 'Test' };
       jest.spyOn(gridStub, 'getDataItem').mockReturnValue(mockProduct);
diff --git a/packages/composite-editor-component/src/slick-composite-editor.component.ts b/packages/composite-editor-component/src/slick-composite-editor.component.ts
index 02be3b9a8..4a2ff69c3 100644
--- a/packages/composite-editor-component/src/slick-composite-editor.component.ts
+++ b/packages/composite-editor-component/src/slick-composite-editor.component.ts
@@ -484,6 +484,11 @@ export class SlickCompositeEditorComponent implements ExternalResource {
         document.body.classList.add('slick-modal-open'); // add backdrop to body
         this._bindEventService.bind(document.body, 'click', this.handleBodyClicked.bind(this));
 
+        // execute lifecycle callback after the modal window is created and rendered in the DOM
+        if (typeof this._options.onRendered === 'function') {
+          this._options.onRendered(this._modalElm);
+        }
+
         this._editors = {};
         this._editorContainers = modalColumns.map(col => modalBodyElm.querySelector<HTMLDivElement>(`[data-editorid=${col.id}]`)) || [];
         this._compositeOptions = { destroy: this.disposeComponent.bind(this), modalType, validationMsgPrefix: '* ', formValues: {}, editors: this._editors };