diff --git a/include/osgGA/StandardManipulator b/include/osgGA/StandardManipulator
index d61565d74..0cb615dd8 100644
--- a/include/osgGA/StandardManipulator
+++ b/include/osgGA/StandardManipulator
@@ -183,7 +183,7 @@ inline bool StandardManipulator::getRelativeFlag( int index ) const
 inline void StandardManipulator::setRelativeFlag( int index, bool value )
 {
     if( value )  _relativeFlags |= (0x01 << index);
-    else  _relativeFlags &= (~0x01 << index);
+    else  _relativeFlags &= ~(0x01 << index);
 }
 
 /// Returns whether manipulator preserves camera's "UP" vector.