diff --git a/R/mully_edge.R b/R/mully_edge.R
index 1fb388d..0100405 100644
--- a/R/mully_edge.R
+++ b/R/mully_edge.R
@@ -58,7 +58,7 @@ getEdgeAttributes<-function(g,nodeStart,nodeDest){
     stop("Invalid Arguments")
   }
   edgeList=as.data.frame(get.edgelist(g),stringsAsFactors = FALSE)
-  attributes=as.data.frame(get.edge.attribute(g),stringsAsFactors = FALSE)
+  attributes=as.data.frame(lapply(edge_attr(g),I),stringsAsFactors = FALSE)
   edgeAttributes=cbind(edgeList,attributes)
   if(missing(nodeStart) && missing(nodeDest)){
     return(edgeAttributes)
@@ -121,6 +121,15 @@ addEdge <- function(g, nodeStart, nodeDest, attributes) {
     g <- set.edge.attribute(g, key, index = idEdge, attributes[[key]])
   }
 
+
+  # attributes of type list that were not specified in 'attributes' should be NULL instead of NA
+  edgeAttributes = edge_attr(g, index=idEdge)
+  for (key in names(edgeAttributes)) {
+    if (is.list(edgeAttributes[[key]]) && is.na(edgeAttributes[[key]])) {
+      g <- set.edge.attribute(g, key, index = idEdge, list(NULL))
+    }
+  }
+
   #name the class
   class(g) = c("mully",class(g))
   return(g)
diff --git a/R/mully_node.R b/R/mully_node.R
index 9af68ca..8fdbfbe 100644
--- a/R/mully_node.R
+++ b/R/mully_node.R
@@ -105,6 +105,14 @@ addNode <- function(g, nodeName, layerName, attributes = NA) {
     }
   }
 
+  # attributes of type list that were not specified in 'attributes' should be NULL instead of NA
+  nodeAttributes = vertex_attr(g, index=idNode)
+  for (key in names(nodeAttributes)) {
+    if (is.list(nodeAttributes[[key]]) && is.na(nodeAttributes[[key]])) {
+      g <- set.vertex.attribute(g, key, index = idNode, list(NULL))
+    }
+  }
+
   #name the class
   class(g) = c("mully",class(g))
   return(g)
@@ -167,7 +175,7 @@ getNodeAttributes<-function(g,nameNode,layerByName=FALSE){
   if(missing(g) || !is.mully(g)){
     stop("Invalid Arguments")
   }
-  attributes=as.data.frame(get.vertex.attribute(g),stringsAsFactors = FALSE)
+  attributes=as.data.frame(lapply(vertex_attr(g),I),stringsAsFactors = FALSE)
   if(layerByName==TRUE){
     attributes$n=g$layers$Name[attributes$n]
   }
@@ -180,23 +188,13 @@ getNodeAttributes<-function(g,nameNode,layerByName=FALSE){
   return(attributes[which(attributes$name==nameNode),])
 }
 
-
 getIDCommonDF<-function(df,df1){
-  #Get the common rows
-  common=merge.data.frame(df,df1)
-  #No Common Rows
-  if(dim(common)[1]==0){
+  common <- merge.data.frame(
+    cbind(rid=rownames(df), df),
+    df1
+  )
+  if (nrow(common) == 0) {
     return(NULL)
   }
-  rownb=dim(df)[1]
-  id=c()
-  for(i in 1:dim(common)[1]){
-    for(j in 1:rownb){
-      test=(df[j,]==common[i,])
-      if(!is.na(test) && !FALSE%in%test){
-        id<-append(id,rownames(df)[j])
-      }
-    }
-  }
-  return(id)
+  common$rid
 }
diff --git a/R/mully_visualization.R b/R/mully_visualization.R
index ed0c118..dad094c 100644
--- a/R/mully_visualization.R
+++ b/R/mully_visualization.R
@@ -11,7 +11,7 @@ getRandomLayout <- function(g) {
   g2 = g
   for (i in 1:getLayersCount(g2)) {
     layer = getLayerByID(g, i)
-    if (is.null(layer) || is.na(layer))
+    if (length(layer) == 0)
       next
 
     repeat {
@@ -30,7 +30,7 @@ getScaledLayout <- function(g) {
   g2 = g
   for (i in 1:getLayersCount(g2)) {
     layer = getLayerByID(g, i)
-    if (is.null(layer) || is.na(layer))
+    if (length(layer) == 0)
       next
 
     xs = (1:length(layer)) * 8 / length(layer)