Fix Firefox 45 tests (click issues, screenshots) (#8533)

tests/screenshots

-Subproject commit ce9907a1e9f05abceeb9be656b4d1d8d58f0d5bf
+Subproject commit c233d26d0af136183eef3707461e2df0d026ff4e

uitest-common/src/main/java/com/vaadin/tests/tb3/AbstractTB3Test.java

         }
     }
 
+    protected void clickElement(WebElement element) {
+        if (BrowserUtil.isFirefox(getDesiredCapabilities())) {
+            // Workaround for Selenium/TB and Firefox 45 issue
+            ((TestBenchElement) (element)).clickHiddenElement();
+        } else {
+            element.click();
+        }
+    }
+
     protected boolean isLoadingIndicatorVisible() {
         WebElement loadingIndicator = findElement(
                 By.className("v-loading-indicator"));

uitest/src/test/java/com/vaadin/tests/components/combobox/ComboBoxClickIconTest.java

 
         $(ComboBoxElement.class).first().openPopup();
 
-        getDriver().findElements(By.className("gwt-MenuItem")).get(1).click();
+        clickElement(
+                getDriver().findElements(By.className("gwt-MenuItem")).get(1));
 
-        getDriver().findElement(By.className("v-filterselect"))
-                .findElement(By.className("v-icon")).click();
+        clickElement(getDriver().findElement(By.className("v-filterselect"))
+                .findElement(By.className("v-icon")));
 
         Assert.assertTrue("Unable to find menu items in combobox popup",
                 isElementPresent(By.className("gwt-MenuItem")));

uitest/src/test/java/com/vaadin/tests/components/combobox/ComboBoxLargeIconsTest.java

         compareScreen("icons-16x16-page1");
         cb.openNextPage();
         compareScreen("icons-16x16-page2");
-        cb.findElement(By.vaadin("#popup/item0")).click();
+        clickElement(cb.findElement(By.vaadin("#popup/item0")));
         compareScreen("icons-16x16-selected-1-3-5-9");
 
         iconSelect.selectByText("32x32");
         ComboBoxElement pageLength0cb = $(ComboBoxElement.class)
                 .caption("Pagelength 0").first();
         pageLength0cb.openPopup();
-        pageLength0cb.findElement(By.vaadin("#popup/item1")).click();
+        clickElement(pageLength0cb.findElement(By.vaadin("#popup/item1")));
 
         ComboBoxElement cb200px = $(ComboBoxElement.class)
                 .caption("200px wide select with 50 items").first();
         cb200px.openPopup();
-        cb200px.findElement(By.vaadin("#popup/item1")).click();
+        clickElement(cb200px.findElement(By.vaadin("#popup/item1")));
 
         ComboBoxElement cb150px = $(ComboBoxElement.class)
                 .caption("150px wide select with 5 items").first();

uitest/src/test/java/com/vaadin/tests/components/ui/ComboboxSelectedItemTextTest.java

 
         // Select an element from the first (to test) combobox.
 
-        comboBox.findElement(By.className("v-filterselect-button")).click();
+        clickElement(
+                comboBox.findElement(By.className("v-filterselect-button")));
         waitForPopup(comboBox);
         WebElement comboBoxPopup = vaadinElement(
                 "/VVerticalLayout[0]/Slot[2]/VVerticalLayout[0]/Slot["
                         + indexToTest + "]/VComboBox[0]#popup");
-        comboBoxPopup.findElements(By.tagName("td")).get(2).click();
+        clickElement(comboBoxPopup.findElements(By.tagName("td")).get(2));
 
         // Select an element from the second (to focus) combobox to remove
         // focus from the first combobox
 
-        comboBoxFocus.findElement(By.className("v-filterselect-button"))
-                .click();
+        clickElement(comboBoxFocus
+                .findElement(By.className("v-filterselect-button")));
         waitForPopup(comboBoxFocus);
         comboBoxPopup = vaadinElement(
                 "/VVerticalLayout[0]/Slot[2]/VVerticalLayout[0]/Slot["
                         + indexToFocus + "]/VComboBox[0]#popup");
-        comboBoxPopup.findElements(By.tagName("td")).get(2).click();
+        clickElement(comboBoxPopup.findElements(By.tagName("td")).get(2));
 
         // click the button of the first combobox. This would reveal the
         // unwanted behaviour.
 
-        comboBox.findElement(By.className("v-filterselect-button")).click();
+        clickElement(
+                comboBox.findElement(By.className("v-filterselect-button")));
 
         // sadly, screenshot comparison is the only reasonable way to test a
         // rendering issue.