diff --git a/UI/Scheduler/UIxAttendeesEditor.m b/UI/Scheduler/UIxAttendeesEditor.m
index 891f8b983..103cb1201 100644
--- a/UI/Scheduler/UIxAttendeesEditor.m
+++ b/UI/Scheduler/UIxAttendeesEditor.m
@@ -20,6 +20,7 @@
  * Boston, MA 02111-1307, USA.
  */
 
+#import <Foundation/NSString.h>
 #import <Common/UIxPageFrame.h>
 
 #import "UIxAttendeesEditor.h"