Restored part that would otherwise cause a StackOverflowError...

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@1067565 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/fop/layoutmgr/BlockLayoutManager.java

@@ -268,7 +268,9 @@ public class BlockLayoutManager extends BlockStackingLayoutManager
                 innerPosition = pos.getPosition();
             }
 
-            if (innerPosition != null) {
+            if (innerPosition != null
+                    && (innerPosition.getLM() != this
+                        || innerPosition instanceof MappingPosition)) {
                 // innerPosition was created by another LM
                 positionList.add(innerPosition);
                 lastLM = innerPosition.getLM();