Attaching a patch for leaks with this backtrace reported by valgrind:

==17671== 2396 bytes in 218 blocks are definitely lost in loss record 16491 of 18116
==17671==    at 0x1B903882: malloc (vg_replace_malloc.c:149)
==17671==    by 0x1C8D6CC5: g_malloc (gmem.c:137)
==17671==    by 0x1C8E7539: g_strdup (gstrfuncs.c:91)
==17671==    by 0x1C883A8C: value_lcopy_string (gvaluetypes.c:307)
==17671==    by 0x1BF7C4F4: gtk_tree_model_get_valist (gtktreemodel.c:1376)
==17671==    by 0x1BF7C5E5: gtk_tree_model_get (gtktreemodel.c:1338)
==17671==    by 0x80A2090: filename_cell_data_func (fm-list-view.c:1273)
==17671==    by 0x1BFA5D4D: gtk_tree_view_column_cell_set_cell_data
(gtktreeviewcolumn.c:2557)
==17671==    by 0x1BF95534: gtk_tree_view_expose (gtktreeview.c:3665)
==17671==    by 0x1BECD4E5: _gtk_marshal_BOOLEAN__BOXED (gtkmarshalers.c:83)
==17671==    by 0x1C8603B0: g_type_class_meta_marshal (gclosure.c:569)
==17671==    by 0x1C860999: g_closure_invoke (gclosure.c:492)
==17671==    by 0x1C86FF1E: signal_emit_unlocked_R (gsignal.c:2523)
==17671==    by 0x1C871033: g_signal_emit_valist (gsignal.c:2254)
==17671==    by 0x1C8715EA: g_signal_emit (gsignal.c:2288)
==17671==    by 0x1BFB3C71: gtk_widget_event_internal (gtkwidget.c:3735)
==17671==    by 0x1BECAF26: gtk_main_do_event (gtkmain.c:1353)