screen: Ignore num-workspaces when using dynamic workspaces

On startup, workspaces are initialized according to the num-workspaces
preference. However when using dynamic workspaces, the actual number
of workspaces in use might be greater than the preference (when
replacing the window manager), forcing windows on those workspaces
to the first workspace.
To fix, ignore the preference completely when using dynamic workspaces
and try to restore the previous number of workspaces (as read from
_NET_NUMBER_OF_DESKTOPS).

https://bugzilla.gnome.org/show_bug.cgi?id=685439

1 files changed, 24 insertions, 1 deletions

diff --git a/src/core/screen.c b/src/core/screen.c
index e49f7d014..03adfef40 100644
--- a/src/core/screen.c
+++ b/src/core/screen.c
@@ -1464,7 +1464,30 @@ update_num_workspaces (MetaScreen *screen,
   MetaWorkspace *last_remaining;
   gboolean need_change_space;
   
-  new_num = meta_prefs_get_num_workspaces ();
+  if (meta_prefs_get_dynamic_workspaces ())
+    {
+      int n_items;
+      gulong *list;
+
+      n_items = 0;
+      list = NULL;
+
+      if (meta_prop_get_cardinal_list (screen->display, screen->xroot,
+                                       screen->display->atom__NET_NUMBER_OF_DESKTOPS,
+                                       &list, &n_items))
+        {
+          new_num = list[0];
+          meta_XFree (list);
+        }
+      else
+        {
+          new_num = 1;
+        }
+    }
+  else
+    {
+      new_num = meta_prefs_get_num_workspaces ();
+    }
 
   g_assert (new_num > 0);