diff --git a/src/shogun/features/CombinedFeatures.cpp b/src/shogun/features/CombinedFeatures.cpp
index ecd6437d201..949f2090d7a 100644
--- a/src/shogun/features/CombinedFeatures.cpp
+++ b/src/shogun/features/CombinedFeatures.cpp
@@ -22,17 +22,17 @@ CCombinedFeatures::CCombinedFeatures()
 {
 	init();
 
-	feature_list=new CList(true);
+	feature_array = new CDynamicObjectArray();
 	num_vec=0;
 }
 
-CCombinedFeatures::CCombinedFeatures(const CCombinedFeatures & orig)
+CCombinedFeatures::CCombinedFeatures(const CCombinedFeatures& orig)
 : CFeatures(0)
 {
 	init();
 
-	feature_list=new CList(true);
-	//todo copy features
+	feature_array=new CDynamicObjectArray();
+	//TODO copy features
 	num_vec=orig.num_vec;
 }
 
@@ -43,36 +43,38 @@ CFeatures* CCombinedFeatures::duplicate() const
 
 CCombinedFeatures::~CCombinedFeatures()
 {
-	SG_UNREF(feature_list);
+	SG_UNREF(feature_array);
 }
 
+//TODO remove from hierarchy in future patch
 int32_t CCombinedFeatures::get_size() const
 {
-	CFeatures* f=(CFeatures*) feature_list
-		->get_current_element();
-	if (f)
-	{
-		int32_t s=f->get_size();
-		SG_UNREF(f)
-			return s;
-	}
-	else
+	if (feature_array->get_num_elements()==0)
 		return 0;
+	CFeatures* f = (CFeatures*) feature_array->get_element(0);
+	if (!f) 
+		return 0;
+	int32_t size = f->get_size();
+	SG_UNREF(f);
+	return size;
 }
 
+
+CFeatures* CCombinedFeatures::get_feature_obj(int32_t idx)
+{
+	return (CFeatures*) feature_array->get_element(idx);
+} 
+
 void CCombinedFeatures::list_feature_objs()
 {
 	SG_INFO("BEGIN COMBINED FEATURES LIST - ")
 	this->list_feature_obj();
 
-	CListElement* current = NULL ;
-	CFeatures* f=get_first_feature_obj(current);
-
-	while (f)
+	for (index_t f_idx=0; f_idx<get_num_feature_obj(); f_idx++)
 	{
+		CFeatures* f = get_feature_obj(f_idx);
 		f->list_feature_obj();
 		SG_UNREF(f);
-		f=get_next_feature_obj(current);
 	}
 
 	SG_INFO("END COMBINED FEATURES LIST - ")
@@ -82,37 +84,29 @@ bool CCombinedFeatures::check_feature_obj_compatibility(CCombinedFeatures* comb_
 {
 	bool result=false;
 
-	if (comb_feat && (this->get_num_feature_obj() == comb_feat->get_num_feature_obj()) )
+	if ( (comb_feat) && (this->get_num_feature_obj() == comb_feat->get_num_feature_obj()) )
 	{
-		CFeatures* f1=this->get_first_feature_obj();
-		CFeatures* f2=comb_feat->get_first_feature_obj();
-
-		if (f1 && f2 && f1->check_feature_compatibility(f2))
+		for (index_t f_idx=0; f_idx<get_num_feature_obj(); f_idx++)
 		{
-			SG_UNREF(f1);
-			SG_UNREF(f2);
-			while( ( (f1=this->get_next_feature_obj()) != NULL )  &&
-				   ( (f2=comb_feat->get_next_feature_obj()) != NULL) )
+			CFeatures* f1=this->get_feature_obj(f_idx);
+			CFeatures* f2=comb_feat->get_feature_obj(f_idx);
+
+			if ( ! (f1 && f2 && f1->check_feature_compatibility(f2)) )
 			{
-				if (!f1->check_feature_compatibility(f2))
-				{
-					SG_UNREF(f1);
-					SG_UNREF(f2);
-					SG_INFO("not compatible, combfeat\n")
-					comb_feat->list_feature_objs();
-					SG_INFO("vs this\n")
-					this->list_feature_objs();
-					return false;
-				}
 				SG_UNREF(f1);
 				SG_UNREF(f2);
+				SG_INFO("not compatible, combfeat\n")
+				comb_feat->list_feature_objs();
+				SG_INFO("vs this\n")
+				this->list_feature_objs();
+				return false;
 			}
-
-			SG_DEBUG("features are compatible\n")
-			result=true;
+			
+			SG_UNREF(f1);
+			SG_UNREF(f2);
 		}
-		else
-			SG_WARNING("first 2 features not compatible\n")
+		SG_DEBUG("features are compatible\n")
+		result=true;
 	}
 	else
 	{
@@ -128,30 +122,15 @@ bool CCombinedFeatures::check_feature_obj_compatibility(CCombinedFeatures* comb_
 
 CFeatures* CCombinedFeatures::get_first_feature_obj()
 {
-	return (CFeatures*) feature_list->get_first_element();
-}
-
-CFeatures* CCombinedFeatures::get_first_feature_obj(CListElement*& current)
-{
-	return (CFeatures*) feature_list->get_first_element(current);
-}
-
-CFeatures* CCombinedFeatures::get_next_feature_obj()
-{
-	return (CFeatures*) feature_list->get_next_element();
-}
-
-CFeatures* CCombinedFeatures::get_next_feature_obj(CListElement*& current)
-{
-	return (CFeatures*) feature_list->get_next_element(current);
+	return get_feature_obj(0);
 }
 
 CFeatures* CCombinedFeatures::get_last_feature_obj()
 {
-	return (CFeatures*) feature_list->get_last_element();
+	return get_feature_obj(get_num_feature_obj()-1);
 }
 
-bool CCombinedFeatures::insert_feature_obj(CFeatures* obj)
+bool CCombinedFeatures::insert_feature_obj(CFeatures* obj, int32_t idx)
 {
 	ASSERT(obj)
 	int32_t n=obj->get_num_vectors();
@@ -163,47 +142,30 @@ bool CCombinedFeatures::insert_feature_obj(CFeatures* obj)
 	}
 
 	num_vec=n;
-	return feature_list->insert_element(obj);
+	return feature_array->insert_element(obj, idx);
 }
 
 bool CCombinedFeatures::append_feature_obj(CFeatures* obj)
 {
-	ASSERT(obj)
-	int32_t n=obj->get_num_vectors();
-
-	if (get_num_vectors()>0 && n!=get_num_vectors())
-	{
-		SG_ERROR("Number of feature vectors does not match (expected %d, "
-				"obj has %d)\n", get_num_vectors(), n);
-	}
-
-	num_vec=n;
-	return feature_list->append_element(obj);
+	return insert_feature_obj(obj, get_num_feature_obj());
 }
 
-bool CCombinedFeatures::delete_feature_obj()
+bool CCombinedFeatures::delete_feature_obj(int32_t idx)
 {
-	CFeatures* f=(CFeatures*)feature_list->delete_element();
-	if (f)
-	{
-		SG_UNREF(f);
-		return true;
-	}
-	else
-		return false;
+	return feature_array->delete_element(idx);
 }
 
 int32_t CCombinedFeatures::get_num_feature_obj()
 {
-	return feature_list->get_num_elements();
+	return feature_array->get_num_elements();
 }
 
 void CCombinedFeatures::init()
 {
 	m_parameters->add(&num_vec, "num_vec",
 					  "Number of vectors.");
-	m_parameters->add((CSGObject**) &feature_list,
-					  "feature_list", "Feature list.");
+	m_parameters->add((CSGObject**) &feature_array,
+					  "feature_array", "Feature array.");
 }
 
 CFeatures* CCombinedFeatures::create_merged_copy(CFeatures* other)
@@ -236,16 +198,15 @@ CFeatures* CCombinedFeatures::create_merged_copy(CFeatures* other)
 	}
 
 	CCombinedFeatures* result=new CCombinedFeatures();
-	CFeatures* current_this=get_first_feature_obj();
-	CFeatures* current_other=casted->get_first_feature_obj();
-	while (current_this)
+	for (index_t f_idx=0; f_idx<get_num_feature_obj(); f_idx++)
 	{
+		CFeatures* current_this=get_feature_obj(f_idx);
+		CFeatures* current_other=casted->get_feature_obj(f_idx);
+
 		result->append_feature_obj(
 				current_this->create_merged_copy(current_other));
 		SG_UNREF(current_this);
 		SG_UNREF(current_other);
-		current_this=get_next_feature_obj();
-		current_other=get_next_feature_obj();
 	}
 
 	SG_DEBUG("leaving %s::create_merged_copy()\n", get_name())
@@ -257,9 +218,10 @@ void CCombinedFeatures::add_subset(SGVector<index_t> subset)
 	SG_DEBUG("entering %s::add_subset()\n", get_name())
 	CSet<CFeatures*>* processed=new CSet<CFeatures*>();
 
-	CFeatures* current=get_first_feature_obj();
-	while (current)
-	{
+	for (index_t f_idx=0; f_idx<get_num_feature_obj(); f_idx++)
+	{	
+		CFeatures* current=get_feature_obj(f_idx);
+	
 		if (!processed->contains(current))
 		{
 			/* remember that subset was added here */
@@ -269,7 +231,6 @@ void CCombinedFeatures::add_subset(SGVector<index_t> subset)
 					current->get_name(), current);
 		}
 		SG_UNREF(current);
-		current=get_next_feature_obj();
 	}
 
 	/* also add subset to local stack to have it for easy access */
@@ -285,9 +246,9 @@ void CCombinedFeatures::remove_subset()
 	SG_DEBUG("entering %s::remove_subset()\n", get_name())
 	CSet<CFeatures*>* processed=new CSet<CFeatures*>();
 
-	CFeatures* current=get_first_feature_obj();
-	while (current)
+	for (index_t f_idx=0; f_idx<get_num_feature_obj(); f_idx++)
 	{
+		CFeatures* current=get_feature_obj(f_idx);
 		if (!processed->contains(current))
 		{
 			/* remember that subset was added here */
@@ -297,7 +258,6 @@ void CCombinedFeatures::remove_subset()
 					current->get_name(), current);
 		}
 		SG_UNREF(current);
-		current=get_next_feature_obj();
 	}
 
 	/* also remove subset from local stack to have it for easy access */
@@ -313,9 +273,9 @@ void CCombinedFeatures::remove_all_subsets()
 	SG_DEBUG("entering %s::remove_all_subsets()\n", get_name())
 	CSet<CFeatures*>* processed=new CSet<CFeatures*>();
 
-	CFeatures* current=get_first_feature_obj();
-	while (current)
+	for (index_t f_idx=0; f_idx<get_num_feature_obj(); f_idx++)
 	{
+		CFeatures* current=get_feature_obj(f_idx);
 		if (!processed->contains(current))
 		{
 			/* remember that subset was added here */
@@ -325,7 +285,6 @@ void CCombinedFeatures::remove_all_subsets()
 					current->get_name(), current);
 		}
 		SG_UNREF(current);
-		current=get_next_feature_obj();
 	}
 
 	/* also remove subsets from local stack to have it for easy access */
@@ -343,9 +302,10 @@ CFeatures* CCombinedFeatures::copy_subset(SGVector<index_t> indices)
 
 	/* map to only copy same feature objects once */
 	CMap<CFeatures*, CFeatures*>* processed=new CMap<CFeatures*, CFeatures*>();
-	CFeatures* current=get_first_feature_obj();
-	while (current)
+	for (index_t f_idx=0; f_idx<get_num_feature_obj(); f_idx++)
 	{
+		CFeatures* current=get_feature_obj(f_idx);
+	
 		CFeatures* new_element=NULL;
 
 		/* only copy if not done yet, otherwise, use old copy */
@@ -369,7 +329,6 @@ CFeatures* CCombinedFeatures::copy_subset(SGVector<index_t> indices)
 		SG_UNREF(new_element);
 
 		SG_UNREF(current);
-		current=get_next_feature_obj();
 	}
 
 	SG_UNREF(processed);
diff --git a/src/shogun/features/CombinedFeatures.h b/src/shogun/features/CombinedFeatures.h
index f75eb0abbc1..2ca9d2104d7 100644
--- a/src/shogun/features/CombinedFeatures.h
+++ b/src/shogun/features/CombinedFeatures.h
@@ -14,13 +14,12 @@
 #define _CCOMBINEDFEATURES__H__
 
 #include <shogun/features/Features.h>
-#include <shogun/lib/List.h>
+#include <shogun/lib/DynamicObjectArray.h> 
 
 namespace shogun
 {
-class CFeatures;
-class CList;
-class CListElement;
+class CFeatures; 
+class CDynamicObjectArray;
 
 /** @brief The class CombinedFeatures is used to combine a number of of feature objects
  * into a single CombinedFeatures object.
@@ -78,7 +77,7 @@ class CCombinedFeatures : public CFeatures
 			return m_subset_stack->has_subsets()
 					? m_subset_stack->get_size() : num_vec;
 		}
-
+	
 		/** get memory footprint of one feature
 		 *
 		 * @return memory footprint of one feature
@@ -100,26 +99,13 @@ class CCombinedFeatures : public CFeatures
 		 * @return first feature object
 		 */
 		CFeatures* get_first_feature_obj();
-
-		/** get first feature object
-		 *
-		 * @param current list of features
-		 * @return first feature object
-		 */
-		CFeatures* get_first_feature_obj(CListElement*& current);
-
-		/** get next feature object
-		 *
-		 * @return next feature object
-		 */
-		CFeatures* get_next_feature_obj();
-
-		/** get next feature object
-		 *
-		 * @param current list of features
-		 * @return next feature object
-		 */
-		CFeatures* get_next_feature_obj(CListElement*& current);
+		
+		/** get feature object at index idx
+		*
+		* @param idx index of feature object
+		* @return the feature object at index idx
+		*/
+		CFeatures* get_feature_obj(int32_t idx);
 
 		/** get last feature object
 		 *
@@ -127,25 +113,28 @@ class CCombinedFeatures : public CFeatures
 		 */
 		CFeatures* get_last_feature_obj();
 
-		/** insert feature object
+		/** insert feature object at index idx
 		 *
 		 * @param obj feature object to insert
+		 * @param idx the index where to insert the feature object
 		 * @return if inserting was successful
 		 */
-		bool insert_feature_obj(CFeatures* obj);
+		bool insert_feature_obj(CFeatures* obj, int32_t idx);
 
-		/** append feature object
+		/** append feature object to the end of this CombinedFeatures object array
+		 *  convience method for insert_feature_obj(obj, get_num_feature_obj())
 		 *
 		 * @param obj feature object to append
 		 * @return if appending was successful
 		 */
 		bool append_feature_obj(CFeatures* obj);
 
-		/** delete feature object
+		/** delete feature object at position idx
 		 *
+		 * @param idx the index of the feature object to delete
 		 * @return if deleting was successful
 		 */
-		bool delete_feature_obj();
+		bool delete_feature_obj(int32_t idx);
 
 		/** get number of feature objects
 		 *
@@ -204,8 +193,8 @@ class CCombinedFeatures : public CFeatures
 		void init();
 
 	protected:
-		/** feature list */
-		CList* feature_list;
+		/* feature array */
+		CDynamicObjectArray* feature_array;
 
 		/** number of vectors
 		 * must match between sub features
diff --git a/src/shogun/kernel/CombinedKernel.cpp b/src/shogun/kernel/CombinedKernel.cpp
index 838b9f7a0ac..ecfcd2ef59e 100644
--- a/src/shogun/kernel/CombinedKernel.cpp
+++ b/src/shogun/kernel/CombinedKernel.cpp
@@ -101,16 +101,15 @@ bool CCombinedKernel::init(CFeatures* l, CFeatures* r)
 	CKernel* k=NULL;
 
 	bool result=true;
-
-	CListElement* lfc = NULL;
-	CListElement* rfc = NULL;
-	lf=((CCombinedFeatures*) l)->get_first_feature_obj(lfc);
-	rf=((CCombinedFeatures*) r)->get_first_feature_obj(rfc);
+	index_t f_idx = 0;
 
 	SG_DEBUG("Starting for loop for kernels\n")
 	for (index_t k_idx=0; k_idx<get_num_kernels() && result; k_idx++)
 	{
 		k = get_kernel(k_idx);
+		lf = ((CCombinedFeatures*) l)->get_feature_obj(f_idx);
+		rf = ((CCombinedFeatures*) r)->get_feature_obj(f_idx);
+		f_idx++;
 
 		// skip over features - the custom kernel does not need any
 		if (k->get_kernel_type() != K_CUSTOM)
@@ -124,12 +123,7 @@ bool CCombinedKernel::init(CFeatures* l, CFeatures* r)
 			}
 
 			SG_DEBUG("Initializing 0x%p - \"%s\"\n", this, k->get_name())
-			result=k->init(lf,rf);
-			SG_UNREF(lf);
-			SG_UNREF(rf);
-
-			lf=((CCombinedFeatures*) l)->get_next_feature_obj(lfc) ;
-			rf=((CCombinedFeatures*) r)->get_next_feature_obj(rfc) ;
+			result=k->init(lf,rf);		
 		}
 		else
 		{
@@ -143,7 +137,8 @@ bool CCombinedKernel::init(CFeatures* l, CFeatures* r)
 		}
 
 		SG_UNREF(k);
-		k = NULL;
+		SG_UNREF(lf);
+		SG_UNREF(rf);	
 	}
 
 	if (!result)
@@ -156,13 +151,9 @@ bool CCombinedKernel::init(CFeatures* l, CFeatures* r)
 		return false;
 	}
 
-	if ((lf!=NULL) || (rf!=NULL) || (k!=NULL))
-	{
-		SG_UNREF(lf);
-		SG_UNREF(rf);
-		SG_UNREF(k);
+	if ( (f_idx!=((CCombinedFeatures*) l)->get_num_feature_obj()) ||
+			(f_idx!=((CCombinedFeatures*) r)->get_num_feature_obj()) )
 		SG_ERROR("CombinedKernel: Number of features/kernels does not match - bailing out\n")
-	}
 
 	init_normalizer();
 	initialized=true;
diff --git a/src/shogun/kernel/ProductKernel.cpp b/src/shogun/kernel/ProductKernel.cpp
index abe0c1f04e4..ace6b47bab5 100644
--- a/src/shogun/kernel/ProductKernel.cpp
+++ b/src/shogun/kernel/ProductKernel.cpp
@@ -45,18 +45,19 @@ bool CProductKernel::init(CFeatures* l, CFeatures* r)
 
 	bool result=true;
 
-	CListElement* lfc = NULL;
-	CListElement* rfc = NULL;
-	lf=((CCombinedFeatures*) l)->get_first_feature_obj(lfc);
-	rf=((CCombinedFeatures*) r)->get_first_feature_obj(rfc);
 	CListElement* current = NULL;
 	k=get_first_kernel(current);
+	
+	index_t f_idx=0;
 
 	while ( result && k )
 	{
 		// skip over features - the custom kernel does not need any
 		if (k->get_kernel_type() != K_CUSTOM)
 		{
+			lf=((CCombinedFeatures*) l)->get_feature_obj(f_idx);
+			rf=((CCombinedFeatures*) r)->get_feature_obj(f_idx);
+			f_idx++;
 			if (!lf || !rf)
 			{
 				SG_UNREF(lf);
@@ -67,11 +68,6 @@ bool CProductKernel::init(CFeatures* l, CFeatures* r)
 
 			SG_DEBUG("Initializing 0x%p - \"%s\"\n", this, k->get_name())
 			result=k->init(lf,rf);
-			SG_UNREF(lf);
-			SG_UNREF(rf);
-
-			lf=((CCombinedFeatures*) l)->get_next_feature_obj(lfc) ;
-			rf=((CCombinedFeatures*) r)->get_next_feature_obj(rfc) ;
 		}
 		else
 		{
@@ -85,6 +81,8 @@ bool CProductKernel::init(CFeatures* l, CFeatures* r)
 		}
 
 		SG_UNREF(k);
+		SG_UNREF(lf);
+		SG_UNREF(rf);
 		k=get_next_kernel(current) ;
 	}
 
@@ -98,10 +96,9 @@ bool CProductKernel::init(CFeatures* l, CFeatures* r)
 		return false;
 	}
 
-	if ((lf!=NULL) || (rf!=NULL) || (k!=NULL))
+	if ( (f_idx!=((CCombinedFeatures*) l)->get_num_feature_obj()) || 
+			(f_idx!=((CCombinedFeatures*) r)->get_num_feature_obj()) )
 	{
-		SG_UNREF(lf);
-		SG_UNREF(rf);
 		SG_UNREF(k);
 		SG_ERROR("ProductKernel: Number of features/kernels does not match - bailing out\n")
 	}
diff --git a/src/shogun/ui/GUIFeatures.cpp b/src/shogun/ui/GUIFeatures.cpp
index 8ef46157175..4e8698954e6 100644
--- a/src/shogun/ui/GUIFeatures.cpp
+++ b/src/shogun/ui/GUIFeatures.cpp
@@ -280,7 +280,7 @@ bool CGUIFeatures::set_convert_features(CFeatures* features, char* target)
 	if (features_prev->get_feature_class()==C_COMBINED)
 	{
 		CCombinedFeatures* combined=(CCombinedFeatures*) features_prev;
-		combined->delete_feature_obj();
+		combined->delete_feature_obj(combined->get_num_feature_obj()-1);
 		combined->append_feature_obj(features);
 		combined->list_feature_objs();
 	}
@@ -695,7 +695,7 @@ bool CGUIFeatures::del_last_feature_obj(char* target)
 	else
 		SG_ERROR("Unknown target %s, neither TRAIN nor TEST.\n", target)
 
-	if (!cf->delete_feature_obj())
+	if (!cf->delete_feature_obj(cf->get_num_feature_obj()-1))
 		SG_ERROR("No features available to delete.\n")
 
 	return false;
diff --git a/src/shogun/ui/GUIPreprocessor.cpp b/src/shogun/ui/GUIPreprocessor.cpp
index cece7ec98f0..a53323009c3 100644
--- a/src/shogun/ui/GUIPreprocessor.cpp
+++ b/src/shogun/ui/GUIPreprocessor.cpp
@@ -162,32 +162,32 @@ bool CGUIPreprocessor::attach_preproc(char* target, bool do_force)
 			{
 				if (((CCombinedFeatures*) f_train)->check_feature_obj_compatibility((CCombinedFeatures*) f_test))
 				{
-					//preprocess the last test feature obj
-					CFeatures* te_feat=((CCombinedFeatures*) f_test)->get_first_feature_obj();
-					CFeatures* tr_feat=((CCombinedFeatures*) f_train)->get_first_feature_obj();
-
+					
 					int32_t num_combined=((CCombinedFeatures*) f_test)->get_num_feature_obj();
 					ASSERT(((CCombinedFeatures*) f_train)->get_num_feature_obj()==num_combined)
 
-					if (!(num_combined && tr_feat && te_feat))
+					if (!num_combined)
 						SG_ERROR("One of the combined features has no sub-features ?!\n")
-
+					
+					//preprocess the last test feature obj
 					SG_INFO("BEGIN PREPROCESSING COMBINED FEATURES (%d sub-featureobjects).\n", num_combined)
+					index_t f_idx = 0;		
+					for (; f_idx<num_combined; f_idx++)
+					{										
+						CFeatures* te_feat=((CCombinedFeatures*) f_test)->get_feature_obj(f_idx);
+						CFeatures* tr_feat=((CCombinedFeatures*) f_train)->get_feature_obj(f_idx);
+
+						if (!(te_feat && tr_feat))
+							break;
 
-					int32_t n=0;
-					while (n<num_combined && tr_feat && te_feat)
-					{
 						// and preprocess using that one
 						SG_INFO("TRAIN ")
 						tr_feat->list_feature_obj();
 						SG_INFO("TEST ")
 						te_feat->list_feature_obj();
-						preprocess_features(tr_feat, te_feat, do_force);
-						tr_feat=((CCombinedFeatures*) f_train)->get_next_feature_obj();
-						te_feat=((CCombinedFeatures*) f_test)->get_next_feature_obj();
-						n++;
+						preprocess_features(tr_feat, te_feat, do_force);				
 					}
-					ASSERT(n==num_combined)
+					ASSERT(f_idx==num_combined)
 					result=true;
 					SG_INFO("END PREPROCESSING COMBINED FEATURES\n")
 				}