Fixed enter submitting form in dropdown

Closes #19549

app/assets/javascripts/gl_dropdown.js.coffee

@@ -24,19 +24,20 @@ class GitLabDropdownFilter
 
     # Key events
     timeout = ""
-    @input.on "keyup", (e) =>
+    @input
+      .on 'keydown', (e) ->
+        keyCode = e.which
+        e.preventDefault() if keyCode is 13
+      .on 'keyup', (e) =>
         keyCode = e.which
 
         return if ARROW_KEY_CODES.indexOf(keyCode) >= 0
 
-      if @input.val() isnt "" and !$inputContainer.hasClass HAS_VALUE_CLASS
+        if @input.val() isnt '' and !$inputContainer.hasClass HAS_VALUE_CLASS
           $inputContainer.addClass HAS_VALUE_CLASS
-      else if @input.val() is "" and $inputContainer.hasClass HAS_VALUE_CLASS
+        else if @input.val() is '' and $inputContainer.hasClass HAS_VALUE_CLASS
           $inputContainer.removeClass HAS_VALUE_CLASS
 
-      if keyCode is 13
-        return false
-
         # Only filter asynchronously only if option remote is set
         if @options.remote
           clearTimeout timeout

app/assets/javascripts/project.js.coffee

@@ -87,5 +87,10 @@ class @Project
         toggleLabel: (obj, $el) ->
           $el.text().trim()
         clicked: (e) ->
-          $dropdown.closest('form').submit()
+          if $('input[name="ref"]').length
+            $form = $dropdown.closest('form')
+            action = $form.attr('action')
+            divider = if action.indexOf('?') < 0 then '?' else '&'
+
+            Turbolinks.visit "#{action}#{divider}#{$form.serialize()}"
       )