diff --git a/superset-frontend/src/dashboard/components/Header/HeaderActionsDropdown/HeaderActionsDropdown.test.tsx b/superset-frontend/src/dashboard/components/Header/HeaderActionsDropdown/HeaderActionsDropdown.test.tsx
index 8779f8ef2f064..8996645079472 100644
--- a/superset-frontend/src/dashboard/components/Header/HeaderActionsDropdown/HeaderActionsDropdown.test.tsx
+++ b/superset-frontend/src/dashboard/components/Header/HeaderActionsDropdown/HeaderActionsDropdown.test.tsx
@@ -21,6 +21,7 @@ import { render, screen } from 'spec/helpers/testing-library';
 import userEvent from '@testing-library/user-event';
 import fetchMock from 'fetch-mock';
 import { HeaderDropdownProps } from 'src/dashboard/components/Header/types';
+import injectCustomCss from 'src/dashboard/util/injectCustomCss';
 import HeaderActionsDropdown from '.';
 
 const createProps = () => ({
@@ -180,7 +181,9 @@ test('should NOT render the "Refresh dashboard" menu item as disabled', async ()
 
 test('should render with custom css', () => {
   const mockedProps = createProps();
+  const { customCss } = mockedProps;
   render(setup(mockedProps));
+  injectCustomCss(customCss);
   expect(screen.getByRole('button')).toHaveStyle('margin-left: 100px');
 });
 
diff --git a/superset-frontend/src/dashboard/components/Header/HeaderActionsDropdown/index.jsx b/superset-frontend/src/dashboard/components/Header/HeaderActionsDropdown/index.jsx
index b86af3da8a89d..b7d368ec32db2 100644
--- a/superset-frontend/src/dashboard/components/Header/HeaderActionsDropdown/index.jsx
+++ b/superset-frontend/src/dashboard/components/Header/HeaderActionsDropdown/index.jsx
@@ -117,8 +117,6 @@ class HeaderActionsDropdown extends React.PureComponent {
   }
 
   UNSAFE_componentWillMount() {
-    injectCustomCss(this.state.css);
-
     SupersetClient.get({ endpoint: '/csstemplateasyncmodelview/api/read' })
       .then(({ json }) => {
         const cssTemplates = json.result.map(row => ({