[gimp] Bug 776294 - Screenshot buttons cannot be clicked

[Kristian Rietveld <kristian src gnome org>]

commit 7c35d75bf9e540408eb3a6b835f31d82a49d07b1
Author: Kristian Rietveld <kris loopnest org>
Date:   Wed Dec 28 16:12:33 2016 +0100

    Bug 776294 - Screenshot buttons cannot be clicked
    
    Disable the new "automatic window tabbing" feature introduced on macOS
    Sierra. It breaks GTK+ applications and we would need proper support for
    this in GTK+ if we want to use it.

 app/gui/gui.c |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)
---
diff --git a/app/gui/gui.c b/app/gui/gui.c
index 2302654..469a024 100644
--- a/app/gui/gui.c
+++ b/app/gui/gui.c
@@ -78,9 +78,21 @@
 #include "session.h"
 #include "splash.h"
 #include "themes.h"
+
 #ifdef GDK_WINDOWING_QUARTZ
 #import <AppKit/AppKit.h>
 #include <gtkosxapplication.h>
+
+/* Forward declare since we are building against old SDKs. */
+#if !defined(MAC_OS_X_VERSION_10_12) || \
+    MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_12
+
+@interface NSWindow(ForwardDeclarations)
++ (void)setAllowsAutomaticWindowTabbing:(BOOL)allow;
+@end
+
+#endif
+
 #endif /* GDK_WINDOWING_QUARTZ */
 
 #include "gimp-intl.h"
@@ -247,6 +259,17 @@ gui_init (Gimp     *gimp,
   /*  disable automatic startup notification  */
   gtk_window_set_auto_startup_notification (FALSE);
 
+#ifdef GDK_WINDOWING_QUARTZ
+  /* Before the first window is created (typically the splash window),
+   * we need to disable automatic tabbing behavior introduced on Sierra.
+   * This is known to cause all kinds of weird issues (see for instance
+   * Bugzilla #776294) and needs proper GTK+ support if we would want to
+   * enable it.
+   */
+  if ([NSWindow respondsToSelector:@selector(setAllowsAutomaticWindowTabbing:)])
+    [NSWindow setAllowsAutomaticWindowTabbing:NO];
+#endif /* GDK_WINDOWING_QUARTZ */
+
   gimp_dnd_init (gimp);
 
   themes_init (gimp);