diff --git a/Headers/gnustep/gui/NSWorkspace.h b/Headers/gnustep/gui/NSWorkspace.h
index 666961bd2..3076115fa 100644
--- a/Headers/gnustep/gui/NSWorkspace.h
+++ b/Headers/gnustep/gui/NSWorkspace.h
@@ -36,6 +36,7 @@
 @class NSString;
 @class NSArray;
 @class NSMutableArray;
+@class NSMutableDictionary;
 @class NSNotificationCenter;
 @class NSImage;
 @class NSView;