Revert "feat(linux): disable GTK3 header bar by default and use regular title…" (#1521)

This reverts commit f0d94fd.

Author: Predidit

linux/my_application.cc

@@ -43,11 +43,25 @@ static void my_application_activate(GApplication* application) {
   MyApplication* self = MY_APPLICATION(application);
   GtkWindow* window =
       GTK_WINDOW(gtk_application_window_new(GTK_APPLICATION(application)));
-  
-  // If have GTK_CSD in env and it is equal to 1 then add the gtk header bar
-  // to always use client side decorations
-  const char* GTK_CSD = getenv("GTK_CSD");
-  if (GTK_CSD && strcmp(GTK_CSD, "1") == 0) {
+
+  // Use a header bar when running in GNOME as this is the common style used
+  // by applications and is the setup most users will be using (e.g. Ubuntu
+  // desktop).
+  // If running on X and not using GNOME then just use a traditional title bar
+  // in case the window manager does more exotic layout, e.g. tiling.
+  // If running on Wayland assume the header bar will work (may need changing
+  // if future cases occur).
+  gboolean use_header_bar = TRUE;
+#ifdef GDK_WINDOWING_X11
+  GdkScreen* screen = gtk_window_get_screen(window);
+  if (GDK_IS_X11_SCREEN(screen)) {
+    const gchar* wm_name = gdk_x11_screen_get_window_manager_name(screen);
+    if (g_strcmp0(wm_name, "GNOME Shell") != 0) {
+      use_header_bar = FALSE;
+    }
+  }
+#endif
+  if (use_header_bar) {
     GtkHeaderBar* header_bar = GTK_HEADER_BAR(gtk_header_bar_new());
     gtk_widget_show(GTK_WIDGET(header_bar));
     gtk_header_bar_set_title(header_bar, "kazumi");
@@ -134,11 +148,6 @@ static void my_application_class_init(MyApplicationClass* klass) {
 static void my_application_init(MyApplication* self) {}
 
 MyApplication* my_application_new() {
-  // Set the program name to the application ID, which helps various systems
-  // like GTK and desktop environments map this running application to its
-  // corresponding .desktop file. This ensures better integration by allowing
-  // the application to be recognized beyond its binary name.
-  g_set_prgname(APPLICATION_ID);
   return MY_APPLICATION(g_object_new(my_application_get_type(),
                                      "application-id", APPLICATION_ID,
                                      "flags", G_APPLICATION_NON_UNIQUE,