diff --git a/test/functional/apps/visualize/_tsvb_time_series.ts b/test/functional/apps/visualize/_tsvb_time_series.ts
index 0a2400a367a76..e60ccd2b1f853 100644
--- a/test/functional/apps/visualize/_tsvb_time_series.ts
+++ b/test/functional/apps/visualize/_tsvb_time_series.ts
@@ -108,7 +108,6 @@ export default function({ getPageObjects, getService }: FtrProviderContext) {
         expect(actualCount).to.be(expectedLegendValue);
       });
 
-      // FLAKY: https://github.com/elastic/kibana/issues/40458
       it('should show the correct count in the legend with "Human readable" duration formatter', async () => {
         await visualBuilder.clickSeriesOption();
         await visualBuilder.changeDataFormatter('Duration');
diff --git a/test/functional/page_objects/visual_builder_page.ts b/test/functional/page_objects/visual_builder_page.ts
index c64d623979313..34cd999b4cd13 100644
--- a/test/functional/page_objects/visual_builder_page.ts
+++ b/test/functional/page_objects/visual_builder_page.ts
@@ -239,7 +239,7 @@ export function VisualBuilderPageProvider({ getService, getPageObjects }: FtrPro
       formatter: 'Bytes' | 'Number' | 'Percent' | 'Duration' | 'Custom'
     ) {
       const formatterEl = await find.byCssSelector('[id$="row"] .euiComboBox');
-      await comboBox.setElement(formatterEl, formatter);
+      await comboBox.setElement(formatterEl, formatter, { clickWithMouse: true });
     }
 
     /**
@@ -260,11 +260,11 @@ export function VisualBuilderPageProvider({ getService, getPageObjects }: FtrPro
     }) {
       if (from) {
         const fromCombobox = await find.byCssSelector('[id$="from-row"] .euiComboBox');
-        await comboBox.setElement(fromCombobox, from);
+        await comboBox.setElement(fromCombobox, from, { clickWithMouse: true });
       }
       if (to) {
         const toCombobox = await find.byCssSelector('[id$="to-row"] .euiComboBox');
-        await comboBox.setElement(toCombobox, to);
+        await comboBox.setElement(toCombobox, to, { clickWithMouse: true });
       }
       if (decimalPlaces) {
         const decimalPlacesInput = await find.byCssSelector('[id$="decimal"]');
diff --git a/test/functional/services/combo_box.ts b/test/functional/services/combo_box.ts
index b8267f0b4cbe3..2e44e0248cabe 100644
--- a/test/functional/services/combo_box.ts
+++ b/test/functional/services/combo_box.ts
@@ -46,13 +46,21 @@ export function ComboBoxProvider({ getService, getPageObjects }: FtrProviderCont
       await this.setElement(comboBox, value);
     }
 
+    private async clickOption(isMouseClick: boolean, element: WebElementWrapper) {
+      return isMouseClick ? await browser.clickMouseButton(element) : await element.click();
+    }
+
     /**
      * set value inside combobox element
      *
      * @param comboBoxElement
      * @param value
      */
-    public async setElement(comboBoxElement: WebElementWrapper, value: string): Promise<void> {
+    public async setElement(
+      comboBoxElement: WebElementWrapper,
+      value: string,
+      options = { clickWithMouse: false }
+    ): Promise<void> {
       log.debug(`comboBox.setElement, value: ${value}`);
       const isOptionSelected = await this.isOptionSelected(comboBoxElement, value);
 
@@ -65,21 +73,22 @@ export function ComboBoxProvider({ getService, getPageObjects }: FtrProviderCont
       await this.openOptionsList(comboBoxElement);
 
       if (value !== undefined) {
-        const options = await find.allByCssSelector(
+        const selectOptions = await find.allByCssSelector(
           `.euiFilterSelectItem[title^="${value.toString().trim()}"]`,
           WAIT_FOR_EXISTS_TIME
         );
 
-        if (options.length > 0) {
-          await options[0].click();
+        if (selectOptions.length > 0) {
+          await this.clickOption(options.clickWithMouse, selectOptions[0]);
         } else {
           // if it doesn't find the item which text starts with value, it will choose the first option
-          await find.clickByCssSelector('.euiFilterSelectItem');
+          const firstOption = await find.byCssSelector('.euiFilterSelectItem');
+          await this.clickOption(options.clickWithMouse, firstOption);
         }
       } else {
-        await find.clickByCssSelector('.euiFilterSelectItem');
+        const firstOption = await find.byCssSelector('.euiFilterSelectItem');
+        await this.clickOption(options.clickWithMouse, firstOption);
       }
-
       await this.closeOptionsList(comboBoxElement);
     }
 
@@ -241,11 +250,11 @@ export function ComboBoxProvider({ getService, getPageObjects }: FtrProviderCont
       value: string
     ): Promise<boolean> {
       log.debug(`comboBox.isOptionSelected, value: ${value}`);
-      const selectedOptions = await comboBoxElement.findAllByClassName(
-        'euiComboBoxPill',
-        WAIT_FOR_EXISTS_TIME
-      );
-      return selectedOptions.length === 1 && (await selectedOptions[0].getVisibleText()) === value;
+      const $ = await comboBoxElement.parseDomContent();
+      const selectedOptions = $('.euiComboBoxPill')
+        .toArray()
+        .map(option => $(option).text());
+      return selectedOptions.length === 1 && selectedOptions[0] === value;
     }
   }