cpu is 100%
it's hard to me to figure where the problem is.

after some debuging i found that execution is not returning from 
gtk_scrolled_window_size_allocate (GtkWidget  *widget, GtkAllocation *allocation) 
gtk+2.0-2.16.0/gtk/gtkscrolledwindow.c:1337

more precisely the do while loop where previous_hvis = 1 and  previous_vvis = 1

   │1416          do                                                                                                                                                                                                │
   │1417            {                                                                                                                                                                                               │
  >│1418              gtk_scrolled_window_relative_allocation (widget, &relative_allocation);                                                                                                                       │
   │1419                                                                                                                                                                                                            │
   │1420              child_allocation.x = relative_allocation.x + allocation->x;                                                                                                                                   │
   │1421              child_allocation.y = relative_allocation.y + allocation->y;                                                                                                                                   │
   │1422              child_allocation.width = relative_allocation.width;                                                                                                                                           │
   │1423              child_allocation.height = relative_allocation.height;                                                                                                                                         │
   │1424                                                                                                                                                                                                            │
   │1425              previous_hvis = scrolled_window->hscrollbar_visible;                                                                                                                                          │
   │1426              previous_vvis = scrolled_window->vscrollbar_visible;                                                                                                                                          │
   │1427                                                                                                                                                                                                            │
   │1428              gtk_widget_size_allocate (bin->child, &child_allocation);                                                                                                                                     │
   │1429                                                                                                                                                                                                            │
   │1430              /* If, after the first iteration, the hscrollbar and the                                                                                                                                      │
   │1431               * vscrollbar flip visiblity, then we need both.                                                                                                                                              │
   │1432               */                                                                                                                                                                                           │
   │1433              if (count &&                                                                                                                                                                                  │
   │1434                  previous_hvis != scrolled_window->hscrollbar_visible &&                                                                                                                                   │
   │1435                  previous_vvis != scrolled_window->vscrollbar_visible)                                                                                                                                     │
   │1436                {                                                                                                                                                                                           │
   │1437                  scrolled_window->hscrollbar_visible = TRUE;                                                                                                                                               │
   │1438                  scrolled_window->vscrollbar_visible = TRUE;                                                                                                                                               │
   │1439                                                                                                                                                                                                            │
   │1440                  /* a new resize is already queued at this point,                                                                                                                                          │
   │1441                   * so we will immediatedly get reinvoked                                                                                                                                                  │
   │1442                   */                                                                                                                                                                                       │
   │1443                  return;                                                                                                                                                                                   │
   │1444                }                                                                                                                                                                                           │
   │1445                                                                                                                                                                                                            │
   │1446              count++;                                                                                                                                                                                      │
   │1447            }                                                                                                                                                                                               │
   │1448          while (previous_hvis != scrolled_window->hscrollbar_visible ||                                                                                                                                    │
   │1449                 previous_vvis != scrolled_window->vscrollbar_visible);