diff --git a/src/osgSim/MultiSwitch.cpp b/src/osgSim/MultiSwitch.cpp
index 9ec03b0b1..d6e744d7d 100644
--- a/src/osgSim/MultiSwitch.cpp
+++ b/src/osgSim/MultiSwitch.cpp
@@ -25,6 +25,7 @@ MultiSwitch::MultiSwitch():
 MultiSwitch::MultiSwitch(const MultiSwitch& sw,const osg::CopyOp& copyop):
     osg::Group(sw,copyop),
     _newChildDefaultValue(sw._newChildDefaultValue),
+    _activeSwitchSet(sw._activeSwitchSet),
     _values(sw._values)
 {
 }