Regression: Using [...] to change language does not activate apply button

Bug: 53736
Change-Id: If52beb73f9f3f74cde63bd846974540682066ab6

tests/browser/features/step_definitions/common_steps.rb

@@ -31,6 +31,15 @@ Given(/^the content language is "(.*?)"$/) do |language|
 	actual.should == code
 end
 
+Given(/^the interface language is "(.*?)"$/) do |language|
+	# phantomjs needs little bit time because it executes the script before
+	# the page is fully loaded
+	sleep 0.5;
+	code = language_to_code(language)
+	actual = @browser.execute_script( "return mw.config.get( 'wgUserLanguage' )" )
+	actual.should == code
+end
+
 def language_to_code(language)
 	case language
 	when 'German'

tests/browser/features/uls_settings_panel.feature

@@ -63,3 +63,13 @@ Feature: ULS settings panel
     Given I temporarily use "Finnish" as the interface language
     When I open "Language" panel of language settings
     Then I see "English (sama kuin sisällön)" as the name of the content language
+
+  @login @reset-preferences-after
+  Scenario: Selecting language via [...] button
+
+    Given I am logged in
+    When I open "Language" panel of language settings
+      And I click the button with the ellipsis
+      And I use the panel to change my interface language to "German"
+      And I apply the changes
+    Then the interface language is "German"