Ticket #3061: fix [en|dis]abling of layout split adjust buttons.

Switching between vertical and horizontal layouts doesn't properly
activate or deactivate the < and > widget buttons in the layout dialog
according to the setting of the mode being switched to.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>

src/filemanager/layout.c

@@ -377,19 +377,26 @@ layout_callback (Widget * w, Widget * sender, widget_msg_t msg, int parm, void *
         {
             if (panels_layout.horizontal_split != radio_widget->sel)
             {
+                int eq;
+
                 panels_layout.horizontal_split = radio_widget->sel;
 
                 if (panels_layout.horizontal_split)
                 {
-                    if (panels_layout.horizontal_equal)
+                    eq = panels_layout.horizontal_equal;
+                    if (eq)
                         panels_layout.top_panel_size = height / 2;
                 }
                 else
                 {
-                    if (panels_layout.vertical_equal)
+                    eq = panels_layout.vertical_equal;
+                    if (eq)
                         panels_layout.left_panel_size = COLS / 2;
                 }
 
+                widget_disable (WIDGET (bleft_widget), eq);
+                widget_disable (WIDGET (bright_widget), eq);
+
                 update_split (h);
                 layout_change ();
                 do_refresh ();