diff --git a/main/Defaults.scala b/main/Defaults.scala
index 3da965be1..8c0919979 100644
--- a/main/Defaults.scala
+++ b/main/Defaults.scala
@@ -54,8 +54,8 @@ object Defaults extends BuildCommon
 		pollInterval :== 500,
 		logBuffered :== false,
 		autoScalaLibrary :== true,
-		onLoad :== idFun[State],
-		onUnload :== idFun[State],
+		onLoad <<= onLoad ?? idFun[State],
+		onUnload <<= onUnload ?? idFun[State],
 		definesClass :== FileValueCache(Locate.definesClass _ ).get,
 		trapExit :== false,
 		trapExit in run :== true,