Which g-t and vte version is this, exactly? Are there any messages on console (or in ~/.xsession-errors) from gnome-terminal ? And which theme ?

Oh, and was that with metacity launching with compositing enabled, or disabled? (gconf key /apps/metacity/general/compositing_manager)

libvte is 1:0.25.90-0ubuntu3 
gnome-terminal : 2.31.90-0ubuntu1

the messages on the ~/.xsession-errors file:

gnome-terminal:12444): Gtk-CRITICAL **: IA__gtk_style_detach: assertion `style->attach_count > 0' failed

(gnome-terminal:12444): Gtk-CRITICAL **: IA__gtk_style_detach: assertion `GTK_IS_STYLE (style)' failed

(gnome-terminal:12444): Gtk-CRITICAL **: IA__gtk_style_attach: assertion `GTK_IS_STYLE (style)' failed

(gnome-terminal:12444): Gtk-CRITICAL **: IA__gtk_style_detach: assertion `GTK_IS_STYLE (style)' failed

the theme i'm currently using is clearlooks.

And it was launched with the compositing disabled. Thank you for the quick reply!.

Hmm, that shouldn't happen, ever. Possibly a theme bug, or gtk.

One more thing: which gtk modules are loaded? (from gconf key/apps/gnome_settings_daemon/gtk-modules, and various env vars) E.g. & esp. the ubuntu dbusmenu (or whatever it's called) thingy?

just the accessibility is loaded (gail:atk-bridge). Thanks again Christian.

This code from commit ac1e78c78e6a39834d35c525be01d50c348d33ba from bug 612484 looks highly suspicious:

        /* Remove the GDK window. */
-       if (widget->window != NULL) {
+       if (window != NULL) {
                /* detach style */
-               gtk_style_detach(widget->style);
+               GtkStyle *style;
 
-               gdk_window_set_user_data(widget->window, NULL);
-               gdk_window_destroy(widget->window);
-               widget->window = NULL;
+               style = gtk_widget_get_style (widget);
+               gtk_style_detach (style);
+
+               gdk_window_set_user_data (window, NULL);
+               gtk_widget_set_window (widget, NULL);
+
+               gdk_window_destroy (window);
        }
[...]

-       widget->style = gtk_style_attach(widget->style, widget->window);
+       style = gtk_widget_get_style (widget);
+       style = gtk_style_attach (style, window);
+       gtk_widget_set_style (widget, style);

Is this code really completely equivalent to the previous code? AFAICT gtk_widget_set_style does more than just setting widget->style. This part should use gtk_widget_style_attach() instead.

(In reply to comment #7)
> This code from commit ac1e78c78e6a39834d35c525be01d50c348d33ba from bug 612484
> looks highly suspicious:
> 
>         /* Remove the GDK window. */
> -       if (widget->window != NULL) {
> +       if (window != NULL) {
>                 /* detach style */
> -               gtk_style_detach(widget->style);
> +               GtkStyle *style;
> 
> -               gdk_window_set_user_data(widget->window, NULL);
> -               gdk_window_destroy(widget->window);
> -               widget->window = NULL;
> +               style = gtk_widget_get_style (widget);
> +               gtk_style_detach (style);
> +
> +               gdk_window_set_user_data (window, NULL);
> +               gtk_widget_set_window (widget, NULL);
> +
> +               gdk_window_destroy (window);
>         }
> [...]

This part looks fine, though a gtk_widget_style_detach() helper function would be a nice addition to gtk+ for symmetry with gtk_widget_style_attach().

 
> -       widget->style = gtk_style_attach(widget->style, widget->window);
> +       style = gtk_widget_get_style (widget);
> +       style = gtk_style_attach (style, window);
> +       gtk_widget_set_style (widget, style);
> 
> Is this code really completely equivalent to the previous code? AFAICT
> gtk_widget_set_style does more than just setting widget->style. This part
> should use gtk_widget_style_attach() instead.

Yeah, it looks like gtk_widget_set_style() is the wrong function to use here, while gtk_widget_style_attach() does exactly what the old code did.  Try this patch?

diff --git a/src/vte.c b/src/vte.c
index abf7473..2464880 100644
--- a/src/vte.c
+++ b/src/vte.c
@@ -8776,9 +8776,7 @@ vte_terminal_realize(GtkWidget *widget)
     }
 #endif /* GTK >= 2.15.1 */
 
-       style = gtk_widget_get_style (widget);
-       style = gtk_style_attach (style, window);
-       gtk_widget_set_style (widget, style);
+       gtk_widget_style_attach (widget);
 
        vte_terminal_ensure_font (terminal);

I committed that fix. Let's see if that fixes this problem...

*** Bug 628796 has been marked as a duplicate of this bug. ***

No dups in a long time; let's assume this fixed it.