issue solved

src/bk/BKNodePlacement.java

@@ -62,14 +62,12 @@ public class BKNodePlacement {
 
 			@Override
 			public ControlFlow runForward(Memory m) {
-				m.declare( "param1", m.read( "graph", Visibility.GLOBAL ), Visibility.GLOBAL );
 				if( m.isDefined( "Called", Visibility.GLOBAL ) )
 				{
-					actions.push( (Memory mem) -> {
-					    m.undeclare( "param1", Visibility.GLOBAL );
-					} );
+					actions.push( (Memory mem) -> {} );
 					return new ControlFlow( ControlFlow.STEP_OVER );
 				}
+                m.declare( "param1", m.read( "graph", Visibility.GLOBAL ), Visibility.GLOBAL );
 				m.declare( "Called", true, Visibility.GLOBAL );
 				actions.push( (Memory mem) -> {
                     m.undeclare( "param1", Visibility.GLOBAL );