diff --git a/src/openrct2-ui/input/MouseInput.cpp b/src/openrct2-ui/input/MouseInput.cpp
index c6ad8aadb4..dec0c52356 100644
--- a/src/openrct2-ui/input/MouseInput.cpp
+++ b/src/openrct2-ui/input/MouseInput.cpp
@@ -961,7 +961,7 @@ namespace OpenRCT2
         {
             windowClass = w->classification;
             windowNumber = w->number;
-            widget = &w->widgets[widgetIndex];
+            widget = widgetIndex == kWidgetIndexNull ? nullptr : &w->widgets[widgetIndex];
         }
 
         InputWidgetOverChangeCheck(windowClass, windowNumber, widgetIndex);