[gnome-system-monitor] Handle the shift-multiselection case too like nautilus (bgo #705970)

[Robert Roth <robertroth src gnome org>]

commit 0fc24ae8c9b69351d84aefce478d49c23f2be402
Author: Robert Roth <robert roth off gmail com>
Date:   Thu Aug 15 00:03:48 2013 +0300

    Handle the shift-multiselection case too like nautilus (bgo #705970)

 src/proctable.cpp |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/proctable.cpp b/src/proctable.cpp
index aae0acb..0c42f89 100644
--- a/src/proctable.cpp
+++ b/src/proctable.cpp
@@ -108,7 +108,7 @@ cb_tree_button_pressed (GtkWidget *widget, GdkEventButton *event, gpointer data)
         return FALSE;
 
     if (!gtk_tree_selection_path_is_selected (app->selection, path)) {
-        if (!(event->state & GDK_CONTROL_MASK))
+        if (!(event->state & (GDK_CONTROL_MASK | GDK_SHIFT_MASK)))
             gtk_tree_selection_unselect_all (app->selection);
         gtk_tree_selection_select_path (app->selection, path);
     }