diff --git a/pcbnew/router/pns_joint.h b/pcbnew/router/pns_joint.h
index 21b1707868..df06458f65 100644
--- a/pcbnew/router/pns_joint.h
+++ b/pcbnew/router/pns_joint.h
@@ -71,7 +71,7 @@ public:
         m_tag.net = aB.m_tag.net;
         m_linkedItems = aB.m_linkedItems;
         m_layers = aB.m_layers;
-        m_locked = false;
+        m_locked = aB.m_locked;
     }
 
     PNS_ITEM* Clone( ) const
@@ -194,6 +194,9 @@ public:
 
         m_layers.Merge( aJoint.m_layers );
 
+        if( aJoint.IsLocked() )
+            m_locked = true;
+
         BOOST_FOREACH( PNS_ITEM* item, aJoint.LinkList() )
         {
             m_linkedItems.Add( item );
diff --git a/pcbnew/router/pns_line_placer.cpp b/pcbnew/router/pns_line_placer.cpp
index 2622903a2c..b51a50ac55 100644
--- a/pcbnew/router/pns_line_placer.cpp
+++ b/pcbnew/router/pns_line_placer.cpp
@@ -871,6 +871,10 @@ bool PNS_LINE_PLACER::FixRoute( const VECTOR2I& aP, PNS_ITEM* aEndItem )
         {
             m_lastNode->Add( pl.Via().Clone() );
             Router()->CommitRouting( m_lastNode );
+
+            m_lastNode = NULL;
+            m_currentNode = NULL;
+
             m_idle = true;
         }
 
@@ -913,6 +917,7 @@ bool PNS_LINE_PLACER::FixRoute( const VECTOR2I& aP, PNS_ITEM* aEndItem )
     Router()->CommitRouting( m_lastNode );
 
     m_lastNode = NULL;
+    m_currentNode = NULL;
 
     if( !realEnd )
     {
diff --git a/pcbnew/router/pns_node.cpp b/pcbnew/router/pns_node.cpp
index 8cf2441b09..fa99dd82a2 100644
--- a/pcbnew/router/pns_node.cpp
+++ b/pcbnew/router/pns_node.cpp
@@ -111,7 +111,7 @@ PNS_NODE* PNS_NODE::Branch()
 
     TRACE( 0, "PNS_NODE::branch %p (parent %p)", child % this );
 
-    m_children.push_back( child );
+    m_children.insert( child );
 
     child->m_depth = m_depth + 1;
     child->m_parent = this;
@@ -145,15 +145,7 @@ void PNS_NODE::unlinkParent()
     if( isRoot() )
         return;
 
-    for( std::vector<PNS_NODE*>::iterator i = m_parent->m_children.begin();
-         i != m_parent->m_children.end(); ++i )
-    {
-        if( *i == this )
-        {
-            m_parent->m_children.erase( i );
-            return;
-        }
-    }
+    m_parent->m_children.erase( this );
 }
 
 
@@ -1125,7 +1117,7 @@ void PNS_NODE::GetUpdatedItems( ITEM_VECTOR& aRemoved, ITEM_VECTOR& aAdded )
 void PNS_NODE::releaseChildren()
 {
     // copy the kids as the PNS_NODE destructor erases the item from the parent node.
-    std::vector<PNS_NODE*> kids = m_children;
+    std::set<PNS_NODE*> kids = m_children;
 
     BOOST_FOREACH( PNS_NODE* node, kids )
     {
diff --git a/pcbnew/router/pns_node.h b/pcbnew/router/pns_node.h
index 2ded9b5939..2c52f6aee4 100644
--- a/pcbnew/router/pns_node.h
+++ b/pcbnew/router/pns_node.h
@@ -383,6 +383,11 @@ public:
 
     PNS_ITEM* FindItemByParent( const BOARD_CONNECTED_ITEM *aParent );
 
+    bool HasChildren() const
+    {
+        return !m_children.empty();
+    }
+
 private:
     struct OBSTACLE_VISITOR;
     typedef boost::unordered_multimap<PNS_JOINT::HASH_TAG, PNS_JOINT> JOINT_MAP;
@@ -454,7 +459,7 @@ private:
     PNS_NODE* m_root;
 
     ///> list of nodes branched from this one
-    std::vector<PNS_NODE*> m_children;
+    std::set<PNS_NODE*> m_children;
 
     ///> hash of root's items that have been changed in this node
     boost::unordered_set<PNS_ITEM*> m_override;
diff --git a/pcbnew/router/pns_shove.cpp b/pcbnew/router/pns_shove.cpp
index a2f513567d..07b977915c 100644
--- a/pcbnew/router/pns_shove.cpp
+++ b/pcbnew/router/pns_shove.cpp
@@ -963,7 +963,7 @@ PNS_SHOVE::SHOVE_STATUS PNS_SHOVE::shoveIteration( int aIter )
         }
     }
     else
-    { // "forward" collisoins
+    { // "forward" collisions
         switch( ni->Kind() )
         {
         case PNS_ITEM::SEGMENT:
@@ -1098,17 +1098,23 @@ PNS_SHOVE::SHOVE_STATUS PNS_SHOVE::ShoveLines( const PNS_LINE& aCurrentHead )
     }
 
     if( !pushLine( head ) )
+    {
+        delete m_currentNode;
+        m_currentNode = parent;
+
         return SH_INCOMPLETE;
+    }
 
     st = shoveMainLoop();
 
-
-    if( ( st == SH_OK || st == SH_HEAD_MODIFIED ) )
+    if( st == SH_OK )
+    {
         runOptimizer( m_currentNode );
 
-    if( m_newHead && st == SH_OK )
-    {
-        st = SH_HEAD_MODIFIED;
+        if( m_newHead )
+            st = m_currentNode->CheckColliding( &(*m_newHead) ) ? SH_INCOMPLETE : SH_HEAD_MODIFIED;
+        else
+            st = m_currentNode->CheckColliding( &head ) ? SH_INCOMPLETE : SH_OK;
     }
 
     m_currentNode->RemoveByMarker( MK_HEAD );