C2022-003-Change-Textboxes-to-RTF-3

PROMS/ReferencedObjects/LibSource/ctlXMLEditLib/ctlXMLEdit.cs

@@ -706,25 +706,20 @@ namespace ctlXMLEditLib
 					object o = myHT[str];
 					hwnd = (RichTextBox) o;
 
-					string result1 = "";
-					string Str = "";
+					StringBuilder result1 = new StringBuilder();
 					char[] chrAry = hwnd.Text.ToCharArray();
 					foreach (int chr in chrAry)
 					{
 						if (chr > 166)
 						{
-							Str = $"\\u{(int)chr}?";							
-							result1 = result1 + Str;
+							result1.Append($"\\u{(int)chr}?");
 						}
 						else
 						{
-							result1 = result1 + (char)chr;
+							result1.Append((char)chr);
 						}
-
 					}
-
-
-					hwnd.Text = result1;
+					hwnd.Text = result1.ToString();
 
 					imgdate = null;
 					// if this is a required field and there is no text, put out an error