diff --git a/src/company_gui.cpp b/src/company_gui.cpp
--- a/src/company_gui.cpp
+++ b/src/company_gui.cpp
@@ -800,8 +800,14 @@ public:
 		}
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->SetWidgetsDisabledState(true, SCLW_WIDGET_CLASS_RAIL, SCLW_WIDGET_CLASS_ROAD, SCLW_WIDGET_CLASS_SHIP, SCLW_WIDGET_CLASS_AIRCRAFT, WIDGET_LIST_END);
 
 		bool current_class_valid = this->livery_class == LC_OTHER;