diff --git a/AppKit/CPPopover.j b/AppKit/CPPopover.j
index 760e4edab..c887fcf7c 100644
--- a/AppKit/CPPopover.j
+++ b/AppKit/CPPopover.j
@@ -30,6 +30,16 @@
 @import "CPView.j"
 @import "_CPPopoverWindow.j"
 
+@protocol CPPopoverDelegate <CPObject>
+
+@optional
+- (BOOL)popoverShouldClose:(CPPopover)aPopover;
+- (void)popoverWillClose:(CPPopover)aPopover;
+- (void)popoverDidClose:(CPPopover)aPopover;
+- (void)popoverWillShow:(CPPopover)aPopover;
+- (void)popoverDidShow:(CPPopover)aPopover;
+
+@end
 
 CPPopoverBehaviorApplicationDefined = 0;
 CPPopoverBehaviorTransient          = 1;
@@ -60,15 +70,15 @@ var CPPopoverDelegate_popover_willShow_     = 1 << 0,
 */
 @implementation CPPopover : CPResponder
 {
-    @outlet CPViewController    _contentViewController  @accessors(property=contentViewController);
-    @outlet id                  _delegate               @accessors(getter=delegate);
+    @outlet CPViewController        _contentViewController  @accessors(property=contentViewController);
+    @outlet id <CPPopoverDelegate>  _delegate               @accessors(getter=delegate);
 
-    BOOL                        _animates               @accessors(getter=animates);
-    int                         _appearance             @accessors(property=appearance);
-    int                         _behavior               @accessors(getter=behavior);
+    BOOL                            _animates               @accessors(getter=animates);
+    int                             _appearance             @accessors(property=appearance);
+    int                             _behavior               @accessors(getter=behavior);
 
-    _CPPopoverWindow            _popoverWindow;
-    int                         _implementedDelegateMethods;
+    _CPPopoverWindow                _popoverWindow;
+    int                             _implementedDelegateMethods;
 }
 
 
@@ -184,7 +194,7 @@ Set the behavior of the CPPopover. It can be:
     [_popoverWindow setStyleMask:[self styleMaskForBehavior]];
 }
 
-- (void)setDelegate:(id)aDelegate
+- (void)setDelegate:(id <CPPopoverDelegate>)aDelegate
 {
     if (_delegate === aDelegate)
         return;