Sin responsable no hay venta

vender.cs

@@ -330,7 +330,11 @@ namespace compabetov2
         }
 
         private void vender_Load(object sender, EventArgs e)
+
+
         {
+            bntImprimir.Enabled = false;
+            responsablecb.SelectedIndexChanged += responsablecb_SelectedIndexChanged;
 
         }
 
@@ -585,6 +589,13 @@ namespace compabetov2
         private void button6_Click(object sender, EventArgs e)
         {
 
+        }
+
+        private void responsablecb_SelectedIndexChanged(object sender, EventArgs e)
+        {
+            bntImprimir.Enabled = responsablecb.SelectedIndex != -1;
+
+
         }
     }
 }