diff --git a/parts/scenes/app_cannon.lua b/parts/scenes/app_cannon.lua
index 6160ffc4..31818b8d 100644
--- a/parts/scenes/app_cannon.lua
+++ b/parts/scenes/app_cannon.lua
@@ -31,7 +31,7 @@ function scene.keyDown(key,isRep)
         SCN.back()
     end
 end
-function scene.mouseDown(k)
+function scene.mouseDown(_,_,k)
     if k==1 then
         scene.keyDown("space")
     end