Correctly handles multi-selected values

Fixes an issue where values couldnlt be unselected

app/assets/javascripts/gl_dropdown.js.coffee

@@ -39,7 +39,7 @@ class GitLabDropdownFilter
         key: @options.keys
       )
 
-    @callback results
+    @options.callback results
 
 class GitLabDropdownRemote
   constructor: (@dataEndpoint, @options) ->
@@ -75,6 +75,7 @@ class GitLabDropdownRemote
 class GitLabDropdown
   LOADING_CLASS = "is-loading"
   PAGE_TWO_CLASS = "is-page-two"
+  ACTIVE_CLASS = "is-active"
 
   constructor: (@el, @options) ->
     self = @
@@ -225,6 +226,12 @@ class GitLabDropdown
     html += "</li>"
 
   rowClicked: (el) ->
+    fieldName = @options.fieldName
+    field = @dropdown.parent().find("input[name='#{fieldName}']")
+
+    if el.hasClass(ACTIVE_CLASS)
+      field.remove()
+    else
       fieldName = @options.fieldName
       selectedIndex = el.parent().index()
       if @renderedData
@@ -232,19 +239,24 @@ class GitLabDropdown
       value = if @options.id then @options.id(selectedObject, el) else selectedObject.id
 
       if @options.multiSelect
-      fieldName = "#{fieldName}[]"
+        oldValue = field.val()
+        if oldValue
+          value = "#{oldValue},#{value}"
       else
-      @dropdown.find('.is-active').removeClass 'is-active'
-      @dropdown.parent().find("input[name='#{fieldName}']").remove()
+        @dropdown.find(ACTIVE_CLASS).removeClass ACTIVE_CLASS
+        field.remove()
 
       # Toggle active class for the tick mark
       el.toggleClass "is-active"
 
       if value
+        if !field.length
           # Create hidden input for form
-      input = "<input type='hidden' name='#{fieldName}' value='#{value}' />"
+          input = "<input type='hidden' name='#{fieldName}' />"
           @dropdown.before input
 
+        @dropdown.parent().find("input[name='#{fieldName}']").val value
+
   selectFirstRow: ->
     selector = '.dropdown-content li:first-child a'
     if @dropdown.find(".dropdown-toggle-page").length

app/assets/javascripts/labels_select.js.coffee

@@ -4,6 +4,8 @@ class @LabelsSelect
       projectId = $(dropdown).data('project-id')
       labelUrl = $(dropdown).data("labels")
       selectedLabel = $(dropdown).data('selected')
+      if selectedLabel
+        selectedLabel = selectedLabel.split(",")
       newLabelField = $('#new_label_name')
       newColorField = $('#new_label_color')
       showNo = $(dropdown).data('show-no')
@@ -63,6 +65,13 @@ class @LabelsSelect
 
             callback data
         renderRow: (label) ->
+          if $.isArray(selectedLabel)
+            selected = ""
+            $.each selectedLabel, (i, selectedLbl) ->
+              selectedLbl = selectedLbl.trim()
+              if selected is "" && label.title is selectedLbl
+                selected = "is-active"
+          else
             selected = if label.title is selectedLabel then "is-active" else ""
 
           "<li>