Fixed issue #1165 - User can not be removed from organization.

app/assets/javascripts/app/lib/app_post/searchable_select.coffee

@@ -12,6 +12,7 @@ class App.SearchableSelect extends Spine.Controller
     'mouseenter .js-back':   'highlightItem'
     'shown.bs.dropdown':     'onDropdownShown'
     'hidden.bs.dropdown':    'onDropdownHidden'
+    'keyup .js-input':       'onKeyUp'
 
   elements:
     '.js-dropdown': 'dropdown'
@@ -120,6 +121,10 @@ class App.SearchableSelect extends Spine.Controller
     $(document).off 'keydown.searchable_select'
     @isOpen = false
 
+  onKeyUp: =>
+    return if @input.val().trim() isnt ''
+    @shadowInput.val('')
+
   toggle: =>
     @currentItem = null
     @$('[data-toggle="dropdown"]').dropdown('toggle')