diff --git a/src/fp/fp0400.cpp b/src/fp/fp0400.cpp
index d3f615342..a2769740d 100644
--- a/src/fp/fp0400.cpp
+++ b/src/fp/fp0400.cpp
@@ -82,6 +82,8 @@ protected:
 	static bool causfa_handler(TMask_field& f, KEY k);
 
 	void fattsel(int dlg, TField_event& e);
+    // Non permette la selezione multipla delle righe
+	void sel();
 	bool on_field_event(TOperable_field& o, TField_event e, long jolly) override;
 	void check_buttons(int p);
 	void next_page(int p) override;
@@ -1031,21 +1033,33 @@ void TPassive_mask::fattsel(const int dlg, TField_event& e)
 	field(F_DATAENDREG).enable(get_bool(F_CONTABIL));
 }
 
+void TPassive_mask::sel()
+{
+	TSheet_field& sf = sfield(F_DOCS);
+	FOR_EACH_SHEET_ROW(sf, nr, row)
+	{
+		if (*row->get(0) == 'X') {
+			row->add("", 0);
+			break;
+		}
+	}
+	sf.force_update();
+}
+
 bool TPassive_mask::on_field_event(TOperable_field& o, TField_event e, long jolly)
 {
 	switch (o.dlg())
 	{
 	case S_SELCODPROT:
-		if(e == fe_modify)
+		if (e == fe_modify) {
 			set_filter_changed();
+			sel();
+		}
 		break;
 	case F_PROT:
 		if(e == fe_init)
 			init();
 		break;
-	case F_DOCS:
-		if (e == se_query_modify)
-			break;
 	case DLG_USER:
 		if (e == fe_button && jolly > 0 && get_fattsel() == FILTER_CONT)
 		{
@@ -1222,9 +1236,7 @@ void TPassive_app::main_loop()
 	TPassive_mask mask(check_f1());
 	load_mask(mask);
 	mask.first_focus(F_DATAINI);
-	while(mask.run() == K_ENTER)
-	{
-	}
+	while (mask.run() == K_ENTER) {}
 	save_field(mask);
 }