Fixing a incompatible ReadOnly TextField color with the NetDriver if its selected. This work with all drivers.

Terminal.Gui/Views/TextField.cs

@@ -213,7 +213,7 @@ namespace Terminal.Gui {
 			int col = 0;
 			int width = Frame.Width + OffSetBackground ();
 			var tcount = text.Count;
-			var roc = new Attribute (Color.DarkGray, Color.Gray);
+			var roc = Colors.Menu.Disabled;
 			for (int idx = p; idx < tcount; idx++) {
 				var rune = text [idx];
 				var cols = Rune.ColumnWidth (rune);