[gtk/wip/chergert/quartz4u] macos: disable decorated for popupwindow

[Christian Hergert <chergert src gnome org>]

commit a23b98d597c0b6b146de83a3d974ca799209de5f
Author: Christian Hergert <chergert redhat com>
Date:   Thu Jun 4 16:47:00 2020 -0700

    macos: disable decorated for popupwindow

 gdk/macos/gdkmacospopupsurface.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/gdk/macos/gdkmacospopupsurface.c b/gdk/macos/gdkmacospopupsurface.c
index d29293fb7b..4f9d16140f 100644
--- a/gdk/macos/gdkmacospopupsurface.c
+++ b/gdk/macos/gdkmacospopupsurface.c
@@ -299,6 +299,7 @@ _gdk_macos_popup_surface_new (GdkMacosDisplay *display,
 
   [window setOpaque:NO];
   [window setBackgroundColor:[NSColor clearColor]];
+  [window setDecorated:NO];
 
 #if 0
   /* NOTE: We could set these to be popup level, but then