diff --git a/src/signs_gui.cpp b/src/signs_gui.cpp
--- a/src/signs_gui.cpp
+++ b/src/signs_gui.cpp
@@ -566,7 +566,7 @@ static WindowDesc _query_sign_edit_desc(
 void HandleClickOnSign(const Sign *si)
 {
 	if (_ctrl_pressed && (si->owner == _local_company || (si->owner == OWNER_DEITY && _game_mode == GM_EDITOR))) {
-		RenameSign(si->index, nullptr);
+		RenameSign(si->index, "");
 		return;
 	}
 	ShowRenameSignWindow(si);