diff --git a/exp_scenario/module/gui/vlayer.lua b/exp_scenario/module/gui/vlayer.lua
index 48ee202d..50b5218e 100644
--- a/exp_scenario/module/gui/vlayer.lua
+++ b/exp_scenario/module/gui/vlayer.lua
@@ -488,6 +488,8 @@ local function update_surface(event)
     end
 end
 
+local e = defines.events
+
 return feature:guard{
     elements = Elements,
     events = {