diff --git a/src/toolbar_gui.cpp b/src/toolbar_gui.cpp
--- a/src/toolbar_gui.cpp
+++ b/src/toolbar_gui.cpp
@@ -222,7 +222,7 @@ static void PopupMainCompanyToolbMenu(Wi
 #endif /* ENABLE_NETWORK */
 
 	for (CompanyID c = COMPANY_FIRST; c < MAX_COMPANIES; c++) {
-		if (!IsValidCompanyID(c)) continue;
+		if (!Company::IsValidID(c)) continue;
 		list->push_back(new DropDownListCompanyItem(c, false, HasBit(grey, c)));
 	}