[gtk/backports-for-4-2: 4/7] fix: make the new nsview as the first responder.

[Matthias Clasen <matthiasc src gnome org>]

commit f9c7b68853d613b8e570e4106c65a8b6c4876b85
Author: Zhi <yfwz100 yeah net>
Date:   Tue Jun 15 00:06:35 2021 +0800

    fix: make the new nsview as the first responder.
    
    Make the new view as the first responder(focused) so the new view can
    accept events from input method.
    
    Fixes #3968.

 gdk/macos/gdkmacosglcontext.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/gdk/macos/gdkmacosglcontext.c b/gdk/macos/gdkmacosglcontext.c
index b785beadc0..e4ef4abcb1 100644
--- a/gdk/macos/gdkmacosglcontext.c
+++ b/gdk/macos/gdkmacosglcontext.c
@@ -145,6 +145,7 @@ ensure_gl_view (GdkMacosGLContext *self)
       [nsview setPostsFrameChangedNotifications: YES];
       [nsview setNeedsDisplay:YES];
       [nswindow setContentView:nsview];
+      [nswindow makeFirstResponder:nsview];
       [nsview release];
 
       if (self->dummy_view != NULL)