Use a UUID for the NSToolbar in unified title and toolbar.

When two NSToolbars in an application share the same identifier, Cocoa
tries to synchronize their state (item position, view mode, etc.), and
this behvavior interferes with and crashes Qt applications in certain
cases when toggling the unified toolbar on and off. Therefore it is
necessary to use a unique identifier for each native toolbar created.

Does not affect Qt 5. This functionality has been removed and an
equivalent will be provided by QtMacExtras which uses a completely
different approach, though I7d5c8d58e45a504480a1ce67065add15cb35ad8f
could be considered Qt 5's rough equivalent to this.

Task-number: QTBUG-19207
Change-Id: I9030d56941d12a2c1f7a328337bf986f1b51eeb8
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/gui/widgets/qmainwindowlayout_mac.mm b/src/gui/widgets/qmainwindowlayout_mac.mm
index c2c90f0..a6b0a03 100644
--- a/src/gui/widgets/qmainwindowlayout_mac.mm
+++ b/src/gui/widgets/qmainwindowlayout_mac.mm
@@ -48,6 +48,7 @@
 #ifndef QT_MAC_USE_COCOA
 #include <Carbon/Carbon.h>
 #else
+#include <quuid.h>
 #include <private/qcocoatoolbardelegate_mac_p.h>
 #import  <private/qcocoawindowdelegate_mac_p.h>
 #endif
@@ -444,7 +445,7 @@ void QMainWindowLayout::insertIntoMacToolbar(QToolBar *before, QToolBar *toolbar
     QMacCocoaAutoReleasePool pool;
     NSToolbar *macToolbar = [window toolbar];
     if (macToolbar == nil) {
-        macToolbar = [[NSToolbar alloc] initWithIdentifier:(NSString *)kQMainWindowMacToolbarID];
+        macToolbar = [[NSToolbar alloc] initWithIdentifier:qt_mac_QStringToNSString(QUuid::createUuid().toString())];
         [macToolbar setDisplayMode:NSToolbarDisplayModeIconOnly];
         [macToolbar setSizeMode:NSToolbarSizeModeRegular];
         [macToolbar setDelegate:[[QT_MANGLE_NAMESPACE(QCocoaToolBarDelegate) alloc] initWithMainWindowLayout:this]];