3 files changed, 19 insertions, 3 deletions
diff --git a/src/gui/kernel/qt_cocoa_helpers_mac.mm b/src/gui/kernel/qt_cocoa_helpers_mac.mm
index 3d4164a..1c4177e 100644
--- a/src/gui/kernel/qt_cocoa_helpers_mac.mm
+++ b/src/gui/kernel/qt_cocoa_helpers_mac.mm
@@ -1069,6 +1069,17 @@ void qt_mac_updateContentBorderMetricts(void * /*OSWindowRef */window, const ::H
 #endif
 }
 
+void qt_mac_showBaseLineSeparator(void * /*OSWindowRef */window, bool show)
+{
+#if QT_MAC_USE_COCOA
+    QMacCocoaAutoReleasePool pool;
+    OSWindowRef theWindow = static_cast<OSWindowRef>(window);
+    NSToolbar *macToolbar = [theWindow toolbar];
+    if (macToolbar)
+        [macToolbar setShowsBaselineSeparator: show];
+#endif
+}
+
 QStringList qt_mac_NSArrayToQStringList(void *nsarray)
 {
     QStringList result;
diff --git a/src/gui/kernel/qt_cocoa_helpers_mac_p.h b/src/gui/kernel/qt_cocoa_helpers_mac_p.h
index 2cc7dee..741edd6 100644
--- a/src/gui/kernel/qt_cocoa_helpers_mac_p.h
+++ b/src/gui/kernel/qt_cocoa_helpers_mac_p.h
@@ -125,6 +125,7 @@ void macWindowSetHasShadow( void * /*OSWindowRef*/ window, bool hasShadow );
 void macWindowFlush(void * /*OSWindowRef*/ window);
 void macSendToolbarChangeEvent(QWidget *widget);
 void qt_mac_updateContentBorderMetricts(void * /*OSWindowRef */window, const ::HIContentBorderMetrics &metrics);
+void qt_mac_showBaseLineSeparator(void * /*OSWindowRef */window, bool show);
 void * /*NSImage */qt_mac_create_nsimage(const QPixmap &pm);
 void qt_mac_update_mouseTracking(QWidget *widget);
 OSStatus qt_mac_drawCGImage(CGContextRef cg, const CGRect *inbounds, CGImageRef);
diff --git a/src/gui/widgets/qtabbar.cpp b/src/gui/widgets/qtabbar.cpp
index 690e624..6b027b1 100644
--- a/src/gui/widgets/qtabbar.cpp
+++ b/src/gui/widgets/qtabbar.cpp
@@ -87,13 +87,17 @@ void QTabBarPrivate::updateMacBorderMetrics()
         // TODO: get metrics to preserve the bottom value
         // TODO: test tab bar position
 
-        // push the black line at the bottom of the menu bar down to the client are so we can paint over it
+        OSWindowRef window = qt_mac_window_for(q);
+
+        // push base line separator down to the client are so we can paint over it (Carbon)
         metrics.top = (documentMode && q->isVisible()) ? 1 : 0;
         metrics.bottom = 0;
         metrics.left = 0;
         metrics.right = 0;
-
-        qt_mac_updateContentBorderMetricts(qt_mac_window_for(q), metrics);
+        qt_mac_updateContentBorderMetricts(window, metrics);
+        
+        // hide the base line separator if the tabs have docuemnt mode enabled (Cocoa)
+        qt_mac_showBaseLineSeparator(window, !documentMode);
     }
 #endif
 }