diff --git a/src/openrct2-ui/windows/Banner.cpp b/src/openrct2-ui/windows/Banner.cpp
index b6d9a70dc7..bb4b06f602 100644
--- a/src/openrct2-ui/windows/Banner.cpp
+++ b/src/openrct2-ui/windows/Banner.cpp
@@ -85,7 +85,7 @@ private:
             (viewportWidget->width()) - 1, (viewportWidget->height()) - 1, Focus(_bannerViewPos));
 
         if (viewport != nullptr)
-            viewport->flags = gConfigGeneral.AlwaysShowGridlines ? VIEWPORT_FLAG_GRIDLINES : 0;
+            viewport->flags = gConfigGeneral.AlwaysShowGridlines ? VIEWPORT_FLAG_GRIDLINES : VIEWPORT_FLAG_NONE;
         Invalidate();
     }
 
diff --git a/src/openrct2-ui/windows/Park.cpp b/src/openrct2-ui/windows/Park.cpp
index c900be1989..c7312ad288 100644
--- a/src/openrct2-ui/windows/Park.cpp
+++ b/src/openrct2-ui/windows/Park.cpp
@@ -628,7 +628,7 @@ private:
         int32_t viewportFlags{};
         if (viewport == nullptr)
         {
-            viewportFlags = gConfigGeneral.AlwaysShowGridlines ? VIEWPORT_FLAG_GRIDLINES : 0;
+            viewportFlags = gConfigGeneral.AlwaysShowGridlines ? VIEWPORT_FLAG_GRIDLINES : VIEWPORT_FLAG_NONE;
         }
         else
         {
diff --git a/src/openrct2-ui/windows/Sign.cpp b/src/openrct2-ui/windows/Sign.cpp
index 0d16eeeaca..79926b55b3 100644
--- a/src/openrct2-ui/windows/Sign.cpp
+++ b/src/openrct2-ui/windows/Sign.cpp
@@ -137,7 +137,7 @@ public:
             this, windowPos + ScreenCoordsXY{ viewportWidget.left + 1, viewportWidget.top + 1 }, viewportWidget.width() - 1,
             viewportWidget.height() - 1, Focus(CoordsXYZ{ signViewPosition, viewZ }));
 
-        viewport->flags = gConfigGeneral.AlwaysShowGridlines ? VIEWPORT_FLAG_GRIDLINES : 0;
+        viewport->flags = gConfigGeneral.AlwaysShowGridlines ? VIEWPORT_FLAG_GRIDLINES : VIEWPORT_FLAG_NONE;
         Invalidate();
 
         return true;
@@ -315,7 +315,7 @@ public:
             this, windowPos + ScreenCoordsXY{ viewportWidget->left + 1, viewportWidget->top + 1 }, viewportWidget->width() - 1,
             viewportWidget->height() - 1, Focus(CoordsXYZ{ signViewPos }));
         if (viewport != nullptr)
-            viewport->flags = gConfigGeneral.AlwaysShowGridlines ? VIEWPORT_FLAG_GRIDLINES : 0;
+            viewport->flags = gConfigGeneral.AlwaysShowGridlines ? VIEWPORT_FLAG_GRIDLINES : VIEWPORT_FLAG_NONE;
         Invalidate();
     }
 
diff --git a/src/openrct2/interface/Viewport.h b/src/openrct2/interface/Viewport.h
index 3c3d9a4399..904ab8ddf9 100644
--- a/src/openrct2/interface/Viewport.h
+++ b/src/openrct2/interface/Viewport.h
@@ -30,6 +30,8 @@ struct PaintEntry;
 // Values can be changed when plugins move to using named constants.
 enum : uint32_t
 {
+    VIEWPORT_FLAG_NONE = 0U,
+
     VIEWPORT_FLAG_GRIDLINES = (1U << 7),
     VIEWPORT_FLAG_UNDERGROUND_INSIDE = (1U << 0),
     VIEWPORT_FLAG_HIDE_BASE = (1U << 12),