diff --git a/cocoa/BrowserWindowController.m b/cocoa/BrowserWindowController.m
index 4ed220015..f30607a8e 100644
--- a/cocoa/BrowserWindowController.m
+++ b/cocoa/BrowserWindowController.m
@@ -22,10 +22,18 @@
 #import "PSMTabBarControl.h"
 #import "PSMRolloverButton.h"
 #import "URLFieldCell.h"
+#import "cocoa/gui.h"
 
 #import "desktop/browser.h"
 #import "desktop/options.h"
 
+@interface BrowserWindowController ()
+
+- (void) canCloseAlertDidEnd:(NSAlert *)alert returnCode:(int)returnCode contextInfo:(void *)contextInfo;
+
+@end
+
+
 @implementation BrowserWindowController
 
 @synthesize tabBar;
@@ -99,6 +107,30 @@
 	}
 }
 
+- (BOOL) windowShouldClose: (NSWindow *) window;
+{
+	if ([tabView numberOfTabViewItems] <= 1) return YES;
+	if ([[NSUserDefaults standardUserDefaults] boolForKey: kAlwaysCloseMultipleTabs]) return YES;
+	
+	NSAlert *ask = [NSAlert alertWithMessageText: @"Do you really want to close this window?" defaultButton:@"Yes" alternateButton:@"No" otherButton:nil 
+					   informativeTextWithFormat: @"There are %d tabs open, do you want to close them all?", [tabView numberOfTabViewItems]];
+	[ask setShowsSuppressionButton:YES];
+	
+	[ask beginSheetModalForWindow: window modalDelegate:self didEndSelector:@selector(canCloseAlertDidEnd:returnCode:contextInfo:) 
+					  contextInfo: NULL];
+
+	return NO;
+}
+
+- (void) canCloseAlertDidEnd:(NSAlert *)alert returnCode:(int)returnCode contextInfo:(void *)contextInfo;
+{
+	if (returnCode == NSOKButton) {
+		[[NSUserDefaults standardUserDefaults] setBool: [[alert suppressionButton] state] == NSOnState 
+												forKey: kAlwaysCloseMultipleTabs];
+		[[self window] close];
+	}
+}
+
 - (void) windowWillClose: (NSNotification *)notification;
 {
 	for (NSTabViewItem *tab in [tabView tabViewItems]) {
diff --git a/cocoa/gui.h b/cocoa/gui.h
index b4b78466e..413727fe6 100644
--- a/cocoa/gui.h
+++ b/cocoa/gui.h
@@ -24,5 +24,6 @@ extern NSString * const kHotlistFileOption;
 extern NSString * const kHomepageURLOption;
 extern NSString * const kOptionsFileOption;
 extern NSString * const kAlwaysCancelDownload;
+extern NSString * const kAlwaysCloseMultipleTabs;
 
 void cocoa_autorelease( void );
diff --git a/cocoa/gui.m b/cocoa/gui.m
index 9bb1bab36..d07d4f902 100644
--- a/cocoa/gui.m
+++ b/cocoa/gui.m
@@ -46,6 +46,7 @@ NSString * const kHotlistFileOption = @"Hotlist";
 NSString * const kHomepageURLOption = @"HomepageURL";
 NSString * const kOptionsFileOption = @"ClassicOptionsFile";
 NSString * const kAlwaysCancelDownload = @"AlwaysCancelDownload";
+NSString * const kAlwaysCloseMultipleTabs = @"AlwaysCloseMultipleTabs";
 
 #define UNIMPL() NSLog( @"Function '%s' unimplemented", __func__ )