diff --git a/automaton.c b/automaton.c
index 73b4f73..8893837 100644
--- a/automaton.c
+++ b/automaton.c
@@ -8,16 +8,23 @@
 /*                              S T A T E S                                   */
 /******************************************************************************/
 
-/*                             (exec / edit)
+/*                             (exec / edit)                   <   MODE
  *                                   X
- *                        (state / rules / data)
+ *                        (state / rules / data)               <   STATUS
  *                                   X
  *                     (measure / analyse / interpret)
  *                                   X
  *                             (read / write)
  */
 
+static int mode = RUN;
+void set_mode (int prescribed) {mode = prescribed;}
+int  get_mode () {return mode;}
+
 static int status = INTER; // int  get_status () {return status;}
+void set_status (int prescribed) {status = prescribed;}
+int  get_status () {return status;}
+
 
 /******************************************************************************/
 /*                          T R A N S I T I O N S                             */
diff --git a/automaton.h b/automaton.h
index 1377caa..da12b02 100644
--- a/automaton.h
+++ b/automaton.h
@@ -3,7 +3,10 @@
 
 void set_status (int prescribed);
 int  get_status ();
+void set_mode (int prescribed);
+int  get_mode ();
 
+enum mode { RUN, EDIT };
 enum choice { INTER, STATE, RULES, DATA };
           //  MEASURE, OBSERVE, INTERPRET, HELP, CONFIGURE };
 
diff --git a/callback.c b/callback.c
index d32e8fb..5bb61c7 100644
--- a/callback.c
+++ b/callback.c
@@ -166,12 +166,23 @@ void on_axis_value_change(GtkAdjustment *adjustment, gpointer data)
 /******************************************************************************/
 /*                             B U T T O N S                                  */
 /******************************************************************************/
-void on_toggle_MODEL_RUN_STOP (GtkWidget *btt_MODEL_RUN_STOP, gpointer data){}
+void on_toggle_MODEL_RUN_STOP (GtkWidget *btt_MODEL_RUN_STOP, gpointer data) {
+  if (strcmp (gtk_button_get_label (GTK_BUTTON (btt_MODEL_RUN_STOP)), "  run  "))
+       gtk_button_set_label (GTK_BUTTON (btt_MODEL_RUN_STOP), "  run  ");
+  else gtk_button_set_label (GTK_BUTTON (btt_MODEL_RUN_STOP), " stop ");
+}
+
 void on_toggle_EXEC_EDIT (GtkWidget *btt_XOR_EXEC_EDIT, GtkWidget *btt_MODEL_RUN_STOP) {
+  if (get_mode()) {
   gtk_button_set_icon_name (GTK_BUTTON (btt_XOR_EXEC_EDIT), "power-profile-balanced-rtl-symbolic");
-  gtk_button_set_icon_name (GTK_BUTTON (btt_XOR_EXEC_EDIT), "preferences-system-symbolic");
-  gtk_button_set_label (GTK_BUTTON (btt_MODEL_RUN_STOP), " run ");
+  gtk_button_set_label (GTK_BUTTON (btt_MODEL_RUN_STOP), "  run  ");
   gtk_widget_set_sensitive (GTK_WIDGET (btt_MODEL_RUN_STOP), TRUE);
+  set_mode (0);
+  } else {
+  gtk_button_set_icon_name (GTK_BUTTON (btt_XOR_EXEC_EDIT), "preferences-system-symbolic");
+  gtk_widget_set_sensitive (GTK_WIDGET (btt_MODEL_RUN_STOP), FALSE);
+  set_mode (1);
+  }
 }
 
 
diff --git a/contain.c b/contain.c
index e76466d..61098dc 100644
--- a/contain.c
+++ b/contain.c
@@ -213,9 +213,9 @@ void window_main_child (GtkWindow *main_window, int selected_page){
     gtk_box_append (page_box, GTK_WIDGET (gtk_separator_new (GTK_ORIENTATION_HORIZONTAL)));
     gtk_box_append (page_box, GTK_WIDGET (get_SPACE_VIEW_box()));
     gtk_box_append (page_box, GTK_WIDGET (gtk_separator_new (GTK_ORIENTATION_HORIZONTAL)));
-    window_main_child_bottom (page_box);
-//    if (get_status ())    gtk_box_append (page_box, GTK_WIDGET (get_TIME_EXEC_controls_box()));
-//    else                  gtk_box_append (page_box, GTK_WIDGET (get_SPACE_EDIT_controls_box()));
+//    window_main_child_bottom (page_box);
+//    if (!get_mode ()) gtk_box_append (page_box, GTK_WIDGET (get_TIME_EXEC_controls_box()));
+//    else             gtk_box_append (page_box, GTK_WIDGET (get_SPACE_EDIT_controls_box()));
     gtk_window_set_child (main_window, GTK_WIDGET (page_box));
     //SWITCH_TO (STATE);
   break;