Initial mutli label filter

app/assets/javascripts/issues.js.coffee

@@ -52,7 +52,9 @@
   filterResults: (form) =>
     $('.issues-holder, .merge-requests-holder').css("opacity", '0.5')
     formAction = form.attr('action')
+    console.log form.find("input[type='hidden'][name='label_names[]']")
     formData = form.serialize()
+    console.log 'formData', formData
     issuesUrl = formAction
     issuesUrl += ("#{if formAction.indexOf("?") < 0 then '?' else '&'}")
     issuesUrl += formData

app/assets/javascripts/labels_select.js.coffee

@@ -234,10 +234,19 @@ class @LabelsSelect
             label.id
 
         hidden: ->
+          page = $('body').data 'page'
+          isIssueIndex = page is 'projects:issues:index'
+          isMRIndex = page is page is 'projects:merge_requests:index'
+          
           $selectbox.hide()
           # display:block overrides the hide-collapse rule
           $value.removeAttr('style')
           if $dropdown.hasClass 'js-multiselect'
+            if $dropdown.hasClass('js-filter-submit') and (isIssueIndex or isMRIndex)
+              Issues.filterResults $dropdown.closest('form')
+            else if $dropdown.hasClass('js-filter-submit')
+              $dropdown.closest('form').submit()
+            else
               saveLabelData()
 
         multiSelect: $dropdown.hasClass 'js-multiselect'

app/views/shared/issuable/_label_dropdown.html.haml

@@ -2,6 +2,7 @@
   = hidden_field_tag(:label_name, params[:label_name])
 .dropdown
   %button.dropdown-menu-toggle.js-label-select.js-filter-submit.js-extra-options{type: "button", data: {toggle: "dropdown", field_name: "label_name", show_no: "true", show_any: "true", selected: params[:label_name], project_id: @project.try(:id), labels: labels_filter_path, default_label: "Label"}}
+  %button.dropdown-menu-toggle.js-label-select.js-filter-submit.js-multiselect.js-extra-options{type: "button", data: {toggle: "dropdown", field_name: "label_name[]", show_no: "true", show_any: "true", selected: params[:label_name], project_id: @project.try(:id), labels: labels_filter_path, default_label: "Label"}}
     %span.dropdown-toggle-text
       = h(params[:label_name].presence || "Label")
     = icon('chevron-down')