diff --git a/CoordinateConverter/DCS/Tools/FormAH64DTC.cs b/CoordinateConverter/DCS/Tools/FormAH64DTC.cs
index a996eb0..98b2ed4 100644
--- a/CoordinateConverter/DCS/Tools/FormAH64DTC.cs
+++ b/CoordinateConverter/DCS/Tools/FormAH64DTC.cs
@@ -1059,7 +1059,7 @@ private void tbOwnshipCallsign_TextChanged(object objsender, EventArgs e)
             TextBox sender = objsender as TextBox;
             string text = sender.Text.ToUpper();
             toolTip.Hide(this);
-            tbOwnshipCallsign.BackColor = default;
+            sender.BackColor = default;
 
             if (string.IsNullOrEmpty(text))
             {
@@ -1091,7 +1091,7 @@ private void tbOwnshipSubscriberID_TextChanged(object objsender, EventArgs e)
             TextBox sender = objsender as TextBox;
             string text = sender.Text.ToUpper();
             toolTip.Hide(this);
-            tbOwnshipCallsign.BackColor = default;
+            sender.BackColor = default;
 
             if (string.IsNullOrEmpty(text))
             {