diff --git a/i/css/home.css b/i/css/home.css
index cac7975..5e3d47b 100755
--- a/i/css/home.css
+++ b/i/css/home.css
@@ -240,6 +240,20 @@
     z-index: 10;
 }
 
+#CanvasMessage
+{
+    position: absolute;
+    right: 48px;
+    z-index: 10;
+    -webkit-touch-callout: none; /* iOS Safari */
+    -webkit-user-select: none; /* Safari */
+    -khtml-user-select: none; /* Konqueror HTML */
+    -moz-user-select: none; /* Firefox */
+    -ms-user-select: none; /* Internet Explorer/Edge */
+    user-select: none; /* Non-prefixed version, currently
+                                  supported by Chrome and Opera */
+}
+
 .MarginLeft
 {
     margin-right: 32px !important;
@@ -326,3 +340,18 @@
         min-width: 0px;
     }
 }
+
+.InlineStyle
+{
+    display:inline;
+}
+
+.PaddingRight
+{
+    padding-right: 8px;
+}
+
+#NewEdgeAction
+{
+    padding-top: 8px;
+}
\ No newline at end of file
diff --git a/lang/en/home.php b/lang/en/home.php
index 0e5d2d7..160ab93 100755
--- a/lang/en/home.php
+++ b/lang/en/home.php
@@ -165,4 +165,12 @@
     $g_lang["alpha"] = "Opacity";
 
     $g_lang["background_style"] = "Background color";
+
+    $g_lang["adjacency_matrix_multigraph_description"] = "Multigraph matrix contains weight of minimum edges between vertices.";
+
+    $g_lang["graph_is_multi_message"]   = "Multigraph does not support all algorithms";
+    $g_lang["graph_is_general_message"] = "";
+
+    $g_lang["replace_edge"] = "replace current";
+    $g_lang["add_edge"] = "add (multigraph)";
 ?>
diff --git a/lang/ru/home.php b/lang/ru/home.php
index 02dbcd0..4eea510 100755
--- a/lang/ru/home.php
+++ b/lang/ru/home.php
@@ -168,4 +168,12 @@
     $g_lang["alpha"] = "Прозрачность";
 
     $g_lang["background_style"] = "Цвет фона";
+
+    $g_lang["adjacency_matrix_multigraph_description"] = "Для мультиграфа матрица содержит значения минимальных дуг между вершинами.";
+
+    $g_lang["replace_edge"] = "заменить текущую";
+    $g_lang["add_edge"] = "добавить (мультиграф)";
+
+    $g_lang["graph_is_multi_message"]   = "Мультиграф не поддерживает все алгоритмы";
+    $g_lang["graph_is_general_message"] = "";
 ?>
diff --git a/script/Algorithms.js b/script/Algorithms.js
index c5df7fb..38a25c3 100644
--- a/script/Algorithms.js
+++ b/script/Algorithms.js
@@ -135,7 +135,11 @@ BaseAlgorithm.prototype.getPriority = function()
     return 0;
 }
 
-
+// Algorithm support multi graph
+BaseAlgorithm.prototype.IsSupportMultiGraph = function()
+{
+    return false;
+}
 
 /**
  * Default handler.
diff --git a/script/Appilcation.js b/script/Appilcation.js
index 3550a01..cf65ba1 100644
--- a/script/Appilcation.js
+++ b/script/Appilcation.js
@@ -79,6 +79,8 @@ Application.prototype.redrawGraph = function()
     if (!this.isTimerRender)
     {
         this._redrawGraph();
+        
+        this.GraphTypeChanged();
     }
 }
 
@@ -417,9 +419,9 @@ Application.prototype.AddNewVertex = function(vertex)
 	return this.graph.AddNewVertex(vertex);
 }
 
-Application.prototype.AddNewEdge = function(edge)
+Application.prototype.AddNewEdge = function(edge, replaceIfExists)
 {
-	return this.graph.AddNewEdge(edge);
+	return this.graph.AddNewEdge(edge, replaceIfExists);
 }
 
 Application.prototype.CreateNewGraph = function(x, y)
@@ -439,20 +441,35 @@ Application.prototype.CreateNewGraphEx = function(x, y, vertexEnume)
     return this.graph.AddNewVertex(new BaseVertex(x, y, vertexEnume));
 }
 
-Application.prototype.CreateNewArc = function(graph1, graph2, isDirect, weight)
+Application.prototype.CreateNewArc = function(graph1, graph2, isDirect, weight, replaceIfExist)
 {
-	var edge = this.AddNewEdge(new BaseEdge(graph1, graph2, isDirect, weight));
-    
-    // Make cruvled for pair.
+	var edge = this.AddNewEdge(new BaseEdge(graph1, graph2, isDirect, weight), replaceIfExist);
+
     var edgeObject = this.graph.edges[edge];
-    if (edgeObject.hasPair)
+    var hasPair    = this.graph.hasPair(edgeObject);
+    var neighbourEdges = this.graph.getNeighbourEdges(edgeObject);
+    
+    if (hasPair)
     {
         if (edgeObject.model.default)
             edgeObject.model.type = EdgeModels.cruvled; 
         
-        var pairEdge = this.FindEdge(graph2.id, graph1.id);
+        var pairEdge = this.graph.FindPairFor(edgeObject);
         if (pairEdge.model.default)
-            pairEdge.model.type = EdgeModels.cruvled; 
+        {
+            pairEdge.model.type = EdgeModels.cruvled;
+            if (pairEdge.vertex1 == edgeObject.vertex1 && pairEdge.vertex2 == edgeObject.vertex2)
+                pairEdge.model.curvedValue = -pairEdge.model.curvedValue;
+        }
+    }
+    else if (neighbourEdges.length >= 2)
+    {
+        var cruvled = this.GetAvalibleCruvledValue(neighbourEdges, edgeObject);
+        if (edgeObject.model.default)
+        {
+            edgeObject.model.type        = EdgeModels.cruvled;
+            edgeObject.model.curvedValue = cruvled;
+        }
     }
     
     return edge;
@@ -462,16 +479,18 @@ Application.prototype.DeleteEdge = function(edgeObject)
 {
     var vertex1 = edgeObject.vertex1;
     var vertex2 = edgeObject.vertex2;
-    var hasPair = edgeObject.hasPair;
+    
+    var hasPair = this.graph.hasPair(edgeObject);
     
 	this.graph.DeleteEdge(edgeObject);
     
     // Make line for pair.
     if (hasPair)
     {
-        var edgeObject = this.FindEdge(vertex2.id, vertex1.id);
-        if (edgeObject.model.default)
-            edgeObject.model.type = EdgeModels.line;
+        var pairEdges = this.FindAllEdges(vertex2.id, vertex1.id);
+        
+        if (pairEdges.length == 1 && pairEdges[0].model.default)
+            pairEdges[0].model.type = EdgeModels.line;
     }
 }
 
@@ -508,6 +527,16 @@ Application.prototype.FindEdge = function(id1, id2)
 	return this.graph.FindEdge(id1, id2);
 }
 
+Application.prototype.FindEdgeAny = function(id1, id2)
+{
+	return this.graph.FindEdgeAny(id1, id2);
+}
+
+Application.prototype.FindAllEdges = function(id1, id2)
+{
+	return this.graph.FindAllEdges(id1, id2);
+}
+
 Application.prototype.FindPath = function(graph1, graph2)
 {
 	var creator = new GraphMLCreater(this.graph.vertices, this.graph.edges);
@@ -1501,3 +1530,39 @@ Application.prototype.ResetBackgroundStyle = function ()
     this.isBackgroundCommonStyleCustom = false;
 }
 
+Application.prototype.GetAvalibleCruvledValue = function(neighbourEdges, originalEdge)
+{
+    var values = [];
+    
+    for (var i = 0; i < neighbourEdges.length; i ++)
+    {
+      var edge          = neighbourEdges[i];
+      var sameDirection = (originalEdge.vertex1.id == edge.vertex1.id);
+      if (edge.model.type == EdgeModels.cruvled)
+      {
+        values[(sameDirection ? edge.model.curvedValue : -edge.model.curvedValue)] = true;
+      }
+    }
+    
+    var changeValue  = DefaultHandler.prototype.curvedValue;
+    var defaultValue = 0.0;
+    var maxSearch    = 10;
+    
+    for (var i = 1; i < maxSearch; i ++)
+    {
+        value = i * changeValue;
+        if (!values.hasOwnProperty(value))
+            return value;
+
+        value = - i * changeValue;
+        if (!values.hasOwnProperty(value))
+            return value;
+    }
+    
+    return defaultValue;
+}
+
+Application.prototype.GraphTypeChanged = function()
+{
+    $("#CanvasMessage").text(this.graph.isMulti() ? g_GrapsIsMultiMessage : g_GrapsIsGeneralMessage);
+}
\ No newline at end of file
diff --git a/script/BaseEdge.js b/script/BaseEdge.js
index ed2f4b1..27a7187 100755
--- a/script/BaseEdge.js
+++ b/script/BaseEdge.js
@@ -14,8 +14,6 @@ function BaseEdge(vertex1, vertex2, isDirect, weight)
     this.isDirect  = isDirect;
     this.weight    = 0;
     this.text      = "";
-    // For direct graph, has pair edge or not.
-    this.hasPair   = false;
     this.useWeight = false;
     this.id        = 0;
     this.model = new EdgeModel();
@@ -32,7 +30,6 @@ BaseEdge.prototype.SaveToXML = function ()
 	       "isDirect=\""   + this.isDirect + "\" " +
 	       "weight=\""     + this.weight   + "\" " +
 	       "useWeight=\""  + this.useWeight + "\" " +
-	       "hasPair=\""    + this.hasPair + "\" " +
 	       "id=\""         + this.id + "\" " +
            "text=\""       + this.text + "\" " +
            "arrayStyleStart=\""       + this.arrayStyleStart + "\" " +
@@ -99,33 +96,7 @@ BaseEdge.prototype.HitTest = function (pos)
 
 BaseEdge.prototype.GetEdgePositionsShift = function()
 {
-    var pairShift = this.vertex1.model.diameter * 0.25;
-    var shift     = (this.hasPair ? pairShift : 0);
-    
-    if (shift == 0 || this.model.type == EdgeModels.cruvled)
-    {
-        return this.GetEdgePositions();
-    }
-    else
-    {
-        var position1 = this.vertex1.position;
-        var position2 = this.vertex2.position;
-        var diameter1 = this.vertex1.model.diameter;
-        var diameter2 = this.vertex2.model.diameter;
-        
-        var direction = position1.subtract(position2);
-        direction.normalize(1.0);
-        var normal = direction.normal();
-        direction = direction.multiply(0.5);
-        position1 = position1.subtract(normal.multiply(shift));
-        position2 = position2.subtract(normal.multiply(shift));
-        diameter1 = Math.sqrt(diameter1 * diameter1 - shift * shift);
-        diameter2 = Math.sqrt(diameter2 * diameter2 - shift * shift);
-        var res = [];
-        res.push(position1.subtract(direction.multiply(diameter1)));
-        res.push(position2.subtract(direction.multiply(-diameter2)));
-        return res;
-    }  
+    return this.GetEdgePositions();
 }
 
 BaseEdge.prototype.GetEdgePositions = function()
diff --git a/script/BaseEdgeDrawer.js b/script/BaseEdgeDrawer.js
index 796d084..7b6b53f 100644
--- a/script/BaseEdgeDrawer.js
+++ b/script/BaseEdgeDrawer.js
@@ -163,7 +163,7 @@ BaseEdgeDrawer.prototype.Draw = function(baseEdge, arcStyle)
     
   if (baseEdge.GetText().length > 0)
   {
-	this.DrawWeight(positions[0], positions[1], baseEdge.GetText(), arcStyle, baseEdge.hasPair);
+	this.DrawWeight(positions[0], positions[1], baseEdge.GetText(), arcStyle, false);
   }
 }
 
@@ -274,7 +274,7 @@ BaseEdgeDrawer.prototype.GetTextCenterPoint = function (position1, position2, ha
   }
     
   var textShift   = Math.min(12 / position1.subtract(position2).length(), 0.4);
-  var centerPoint = Point.interpolate(position1, position2, 0.5 + (hasPair ? textShift : 0));
+  var centerPoint = Point.interpolate(position1, position2, 0.5);
   if (position1.equals(position2))
   {
     centerPoint.y = centerPoint.y - Math.cos(arcStyle.loopShiftAngel) * arcStyle.sizeOfLoop * 2;
diff --git a/script/EventHandlers.js b/script/EventHandlers.js
index e51aef4..9166003 100644
--- a/script/EventHandlers.js
+++ b/script/EventHandlers.js
@@ -419,7 +419,7 @@ ConnectionGraphHandler.prototype.firstObject = null;
 
 ConnectionGraphHandler.prototype.AddNewEdge = function(selectedObject, isDirect)
 {
-	this.app.CreateNewArc(this.firstObject, selectedObject, isDirect, document.getElementById('EdgeWeight').value);
+	this.app.CreateNewArc(this.firstObject, selectedObject, isDirect, document.getElementById('EdgeWeight').value, $("#RadiosReplaceEdge").prop("checked"));
 	this.SelectFirst();					
 	this.app.NeedRedraw();
 }
@@ -431,6 +431,26 @@ ConnectionGraphHandler.prototype.SelectVertex = function(selectedObject)
         var direct = false;
         var handler = this;
         var dialogButtons = {};
+        
+        if (!this.app.graph.isMulti())
+        {
+            var hasEdge        = this.app.graph.FindEdgeAny(this.firstObject.id, selectedObject.id);
+            var hasReverseEdge = this.app.graph.FindEdgeAny(selectedObject.id, this.firstObject.id);
+
+            if (hasEdge == null && hasReverseEdge == null)
+            {
+                $("#RadiosReplaceEdge").prop("checked", true);
+                $("#NewEdgeAction" ).hide();
+            }
+            else
+                $( "#NewEdgeAction" ).show();
+        }
+        else
+        {
+            $("#RadiosAddEdge").prop("checked", true);
+            $("#NewEdgeAction" ).hide();
+        }
+        
         dialogButtons[g_orintEdge] = function() {
                     handler.AddNewEdge(selectedObject, true);						
                     $( this ).dialog( "close" );					
@@ -635,7 +655,12 @@ ShowAdjacencyMatrix.prototype.show = function()
 
 	$( "#AdjacencyMatrixField" ).val(this.app.GetAdjacencyMatrix());	
 	$( "#BadMatrixFormatMessage" ).hide();
-		
+	
+    if (this.app.graph.isMulti())
+        $( "#AdjacencyMatrixMultiGraphDesc").show();
+    else
+        $( "#AdjacencyMatrixMultiGraphDesc").hide();
+    
 	$( "#adjacencyMatrix" ).dialog({
 		resizable: false,
         height: "auto",
diff --git a/script/Graph.js b/script/Graph.js
index 1062ffd..5f16d58 100644
--- a/script/Graph.js
+++ b/script/Graph.js
@@ -16,6 +16,8 @@ function Graph()
 	this.uidEdge = 10000;
 	// Has direction edge.
 	this.hasDirect = false;
+    // Is graph multi
+    this.isMultiGraph = false;
 };
 
 // infinity
@@ -37,43 +39,33 @@ Graph.prototype.AddNewEdgeSafe = function(graph1, graph2, isDirect, weight)
 	return this.AddNewEdge(new BaseEdge(graph1, graph2, isDirect, weight));
 }
 
-Graph.prototype.AddNewEdge = function(edge)
+Graph.prototype.AddNewEdge = function(edge, replaceIfExists)
 {
     edge.id = this.uidEdge;
     this.uidEdge = this.uidEdge + 1;
     
-	var edge1      = this.FindEdge(edge.vertex1.id, edge.vertex2.id);
-	var edgeRevert = this.FindEdge(edge.vertex2.id, edge.vertex1.id);
+	var edge1      = this.FindEdgeAny(edge.vertex1.id, edge.vertex2.id);
+	var edgeRevert = this.FindEdgeAny(edge.vertex2.id, edge.vertex1.id);
 	if (!edge.isDirect)
 	{
-		if (edge1 != null)
-		{
+		if (edge1 != null && replaceIfExists)
 			this.DeleteEdge(edge1);
-		}
-		if (edgeRevert != null)
-		{
+		if (edgeRevert != null && replaceIfExists)
 			this.DeleteEdge(edgeRevert);
-		}
+        
 		this.edges.push(edge);
 	}
 	else
 	{
-		if (edge1 != null)
-		{
+		if (edge1 != null && replaceIfExists)
 			this.DeleteEdge(edge1);
-		}
-		if (edgeRevert != null && !edgeRevert.isDirect)
-		{
+		if (edgeRevert != null && !edgeRevert.isDirect && replaceIfExists)
 			this.DeleteEdge(edgeRevert);
-		}
-		else if (edgeRevert != null)		
-		{
-			edgeRevert.hasPair = true;
-			edge.hasPair = true;
-		}
 		
 		this.edges.push(edge);
 	}
+    
+    this.isMultiGraph = this.checkMutiGraph();
 	
 	return this.edges.length - 1;
 }
@@ -84,16 +76,12 @@ Graph.prototype.DeleteEdge = function(edgeObject)
 	var index = this.edges.indexOf(edgeObject);
 	if (index > -1) 
 	{
-		var edgeRevert = this.FindEdge(edgeObject.vertex2.id, edgeObject.vertex1.id);
-		if (edgeRevert != null && edgeRevert.isDirect)
-		{
-			edgeRevert.hasPair = false;
-		}
 		this.edges.splice(index, 1);
 	}
+    
+    this.isMultiGraph = this.checkMutiGraph();
 }
 
-
 Graph.prototype.DeleteVertex = function(vertexObject)
 {
 	var index = this.vertices.indexOf(vertexObject);
@@ -126,7 +114,13 @@ Graph.prototype.FindVertex = function(id)
 	return res;
 }
 
+// depricated
 Graph.prototype.FindEdge = function(id1, id2)
+{
+	return this.FindEdgeAny(id1, id2);
+}
+
+Graph.prototype.FindEdgeAny = function(id1, id2)
 {
 	var res = null;
 	for (var i = 0; i < this.edges.length; i++)
@@ -142,6 +136,43 @@ Graph.prototype.FindEdge = function(id1, id2)
 	return res;
 }
 
+Graph.prototype.FindEdgeMin = function(id1, id2)
+{
+	var res       = null;
+    var minWeight = this.infinity;
+	for (var i = 0; i < this.edges.length; i++)
+	{
+        var edge = this.edges[i];
+		if ((edge.vertex1.id == id1 && edge.vertex2.id == id2)
+		     || (!edge.isDirect && edge.vertex1.id == id2 && edge.vertex2.id == id1))
+		{
+            if (edge.weight < minWeight)
+            {
+                res       = edge;
+                minWeight = edge.weight;
+            }
+		}
+	}
+	
+	return res;
+}
+
+Graph.prototype.FindAllEdges = function(id1, id2)
+{
+	var res       = [];
+	for (var i = 0; i < this.edges.length; i++)
+	{
+        var edge = this.edges[i];
+		if ((edge.vertex1.id == id1 && edge.vertex2.id == id2)
+		     || (!edge.isDirect && edge.vertex1.id == id2 && edge.vertex2.id == id1))
+		{
+			res.push(edge);
+		}
+	}
+	
+	return res;
+}
+
 Graph.prototype.GetAdjacencyMatrixStr = function ()
 {
 	var matrix = "";
@@ -149,7 +180,7 @@ Graph.prototype.GetAdjacencyMatrixStr = function ()
 	{
 		for (var j = 0; j < this.vertices.length; j++)
 		{	
-			var edge = this.FindEdge (this.vertices[i].id, this.vertices[j].id);
+			var edge = this.FindEdgeMin (this.vertices[i].id, this.vertices[j].id);
 			if (edge != null)
 			{
 				matrix += edge.weight;
@@ -182,7 +213,7 @@ Graph.prototype.GetAdjacencyMatrix = function ()
         for (var j = 0; j < this.vertices.length; j ++)
         {
             var v2 = this.vertices[j];
-            var edge = this.FindEdge(v1.id, v2.id);
+            var edge = this.FindEdgeMin(v1.id, v2.id);
             if (edge != null)
             {
                 matrix[i][j] = edge.GetWeight();
@@ -845,6 +876,8 @@ Graph.prototype.LoadFromXML = function (xmlText, additionalData)
     {
         additionalData["data"] = $additional.attr('data');
     }
+    
+    this.isMultiGraph = this.checkMutiGraph();
 }
 
 Graph.prototype.hasDirectEdge = function ()
@@ -910,3 +943,75 @@ Graph.prototype.getGraphBBox = function (viewportSize)
     
     return new Rect(pointMin, pointMax);
 }
+
+Graph.prototype.hasPair = function (edge)
+{
+	return this.FindPairFor(edge) != null;
+}
+
+Graph.prototype.FindPairFor = function (edge)
+{
+    var res = this.getNeighbourEdges(edge);
+	
+	return res.length == 1 ? res[0] : null;
+}
+
+Graph.prototype.getNeighbourEdges = function (edge)
+{
+	var res = [];
+    
+	for (var i = 0; i < this.edges.length; i++)
+	{
+        var curEdge = this.edges[i];
+        if (curEdge == edge)
+            continue;
+            
+		if ((curEdge.vertex1.id == edge.vertex1.id  && 
+             curEdge.vertex2.id == edge.vertex2.id) ||
+            (curEdge.vertex1.id == edge.vertex2.id  && 
+             curEdge.vertex2.id == edge.vertex1.id))
+		{
+			res.push(curEdge);
+		}
+	}
+	
+	return res;
+}
+
+Graph.prototype.checkMutiGraph = function ()
+{
+	var res = false;
+    
+    var start  = {};
+    
+	for (var i = 0; i < this.edges.length; i++)
+	{
+        var edge = this.edges[i];
+        if (start.hasOwnProperty(edge.vertex1.id) && 
+            start[edge.vertex1.id] == edge.vertex2.id)
+        {
+            res = true;
+            break;
+        }
+        
+        start[edge.vertex1.id] = edge.vertex2.id;
+        if (!edge.isDirect)
+        {
+            if (start.hasOwnProperty(edge.vertex2.id) && 
+                start[edge.vertex2.id] == edge.vertex1.id)
+            {
+                res = true;
+                break;
+            }
+            
+            start[edge.vertex2.id] = edge.vertex1.id;
+        }
+	}
+	
+	return res;
+}
+
+Graph.prototype.isMulti = function ()
+{
+	return this.isMultiGraph;
+}
diff --git a/script/main.js b/script/main.js
index b564b15..8f64a3b 100644
--- a/script/main.js
+++ b/script/main.js
@@ -126,6 +126,21 @@ function createAlgorithmMenu()
             application.SetHandlerMode(this.id);
         }
         
+        var eventData = {};
+        eventData.index     = i;
+        eventData.object    = clone;
+        eventData.algorithm = algorithm;
+        
+        $("#openAlgorithmList").bind('click', eventData, function (_eventData) {
+            var data      = _eventData.data;
+            var algorithm = g_Algorithms[g_AlgorithmIds.indexOf(data.algorithm.id)](application.graph, application);
+            
+            if (application.graph.isMulti() && !algorithm.IsSupportMultiGraph())
+              $(data.object).hide();
+            else
+              $(data.object).show();
+          });
+        
         list.appendChild(clone);
         index++;
     }
diff --git a/script/plugins/BFS.js b/script/plugins/BFS.js
index 3458d69..aceac51 100755
--- a/script/plugins/BFS.js
+++ b/script/plugins/BFS.js
@@ -92,7 +92,7 @@ BFSAlgorithm.prototype.bfs = function(vertex, vertexArray, edgeArray)
     for (var i = 0; i < this.graph.vertices.length; i ++)
     {
         var nextVertex = this.graph.vertices[i];
-        var edge       = this.graph.FindEdge(vertex.id, nextVertex.id);
+        var edge       = this.graph.FindEdgeAny(vertex.id, nextVertex.id);
         if (edge && !vertexArray.includes(nextVertex))
         {
             edgeArray.push(edge);
@@ -104,6 +104,12 @@ BFSAlgorithm.prototype.bfs = function(vertex, vertexArray, edgeArray)
     return false;
 }
 
+// Algorithm support multi graph
+BFSAlgorithm.prototype.IsSupportMultiGraph = function()
+{
+    return true;
+}
+
 // Factory for connected components.
 function CreateBFSAlgorithm(graph, app)
 {
diff --git a/script/plugins/Coloring.js b/script/plugins/Coloring.js
index be85891..ec4d728 100755
--- a/script/plugins/Coloring.js
+++ b/script/plugins/Coloring.js
@@ -369,6 +369,12 @@ Coloring.prototype.getPriority = function()
     return -9.0;
 }
 
+// Algorithm support multi graph
+Coloring.prototype.IsSupportMultiGraph = function()
+{
+    return true;
+}
+
 
 // Factory for connected components.
 function CreateColoring(graph, app)
diff --git a/script/plugins/ConnectedComponent.js b/script/plugins/ConnectedComponent.js
index 30da3e5..0acab83 100755
--- a/script/plugins/ConnectedComponent.js
+++ b/script/plugins/ConnectedComponent.js
@@ -76,7 +76,7 @@ FindConnectedComponentNew.prototype.calculate = function(fillUpText = false)
                 for (j = 0; j < connectedVertex[stackElement.id].length; j++)
                 {
                     var nextVertex = connectedVertex[stackElement.id][j];
-                    var connectedEdge = this.graph.FindEdge(stackElement.id, nextVertex.id);
+                    var connectedEdge = this.graph.FindEdgeAny(stackElement.id, nextVertex.id);
                     if (stack.indexOf(nextVertex) < 0)
                     {
                         stack.push(nextVertex);
@@ -113,6 +113,12 @@ FindConnectedComponentNew.prototype.getPriority = function()
     return 0;
 }
 
+// Algorithm support multi graph
+FindConnectedComponentNew.prototype.IsSupportMultiGraph = function()
+{
+    return true;
+}
+
 
 // Factory for connected components.
 function CreateConnectedComponetsNew(graph, app)
diff --git a/script/plugins/DFS.js b/script/plugins/DFS.js
index 1d3db38..a09ae42 100755
--- a/script/plugins/DFS.js
+++ b/script/plugins/DFS.js
@@ -91,7 +91,7 @@ DFSAlgorithm.prototype.dfs = function(vertex, vertexArray, edgeArray)
     for (var i = 0; i < this.graph.vertices.length; i ++)
     {
         var nextVertex = this.graph.vertices[i];
-        var edge        = this.graph.FindEdge(vertex.id, nextVertex.id);
+        var edge        = this.graph.FindEdgeAny(vertex.id, nextVertex.id);
         if (edge && !vertexArray.includes(nextVertex))
         {
             edgeArray.push(edge);
@@ -103,6 +103,12 @@ DFSAlgorithm.prototype.dfs = function(vertex, vertexArray, edgeArray)
     return false;
 }
 
+// Algorithm support multi graph
+DFSAlgorithm.prototype.IsSupportMultiGraph = function()
+{
+    return true;
+}
+
 // Factory for connected components.
 function CreateDFSAlgorithm(graph, app)
 {
diff --git a/script/plugins/Floid.js b/script/plugins/Floid.js
index 375c58b..8d864ee 100755
--- a/script/plugins/Floid.js
+++ b/script/plugins/Floid.js
@@ -103,7 +103,7 @@ FloidAlgorithm.prototype.resultMatrix = function()
         for (var j = 0; j < this.graph.vertices.length; j ++)
         {
             var v2 = this.graph.vertices[j];
-            var edge = this.graph.FindEdge(v1.id, v2.id);
+            var edge = this.graph.FindEdgeMin(v1.id, v2.id);
             if (edge != null)
             {
                 this.matrix[i][j] = edge.GetWeight();
diff --git a/script/plugins/GraphReorder.js b/script/plugins/GraphReorder.js
index 74c60a7..931e762 100755
--- a/script/plugins/GraphReorder.js
+++ b/script/plugins/GraphReorder.js
@@ -159,6 +159,11 @@ GraphReorder.prototype.getPriority = function()
     return -8.5;
 }
 
+// Algorithm support multi graph
+GraphReorder.prototype.IsSupportMultiGraph = function()
+{
+    return true;
+}
 
 // Factory for connected components.
 function CreateAlgorithmGraphReorder(graph, app)
diff --git a/script/plugins/MinimumSpanningTree.js b/script/plugins/MinimumSpanningTree.js
index 109d8d9..f0d51db 100755
--- a/script/plugins/MinimumSpanningTree.js
+++ b/script/plugins/MinimumSpanningTree.js
@@ -104,7 +104,7 @@ MinimumSpanningTree.prototype.resultStartedFrom = function(vertex, connectedVert
                 for (j = 0; j < connectedVertex[element.id].length; j++)
                 {
                     var connectedElement = connectedVertex[element.id][j];
-                    var connectedEdge    = this.graph.FindEdge(element.id, connectedElement.id);
+                    var connectedEdge    = this.graph.FindEdgeMin(element.id, connectedElement.id);
                     if (inTree.indexOf(connectedElement) < 0)
                     {
 						if (minEdge == null || minEdge.weight > connectedEdge.weight)
diff --git a/script/plugins/ModernGraphStyle.js b/script/plugins/ModernGraphStyle.js
index cd35adb..d1917fc 100755
--- a/script/plugins/ModernGraphStyle.js
+++ b/script/plugins/ModernGraphStyle.js
@@ -182,7 +182,6 @@ ModernGraphStyle.prototype.getObjectSelectedGroup = function(object)
     return 0;
 }
 
-
 // Factory for connected components.
 function CreateAlgorithmModernGraphStyle(graph, app)
 {
diff --git a/script/plugins/RadiusAndDiameter.js b/script/plugins/RadiusAndDiameter.js
index db5ae19..ff176cc 100755
--- a/script/plugins/RadiusAndDiameter.js
+++ b/script/plugins/RadiusAndDiameter.js
@@ -183,7 +183,7 @@ RadiusAndDiameter.prototype.getPathByMatrix = function(adjacencyMatrix, minPathM
             if (minPathMatrix[i][finishNode] == length - adjacencyMatrix[startNode][i] && i != startNode)
             {
                 res.push(vertices[startNode]);
-                res.push(this.graph.FindEdge(vertices[startNode].id, vertices[i].id));
+                res.push(this.graph.FindEdgeMin(vertices[startNode].id, vertices[i].id));
                 
                 length -= adjacencyMatrix[startNode][i];
                 startNode = i;
@@ -193,7 +193,7 @@ RadiusAndDiameter.prototype.getPathByMatrix = function(adjacencyMatrix, minPathM
     }
     
     res.push(vertices[startNode]);
-    res.push(this.graph.FindEdge(vertices[startNode].id, vertices[finishNode].id));
+    res.push(this.graph.FindEdgeMin(vertices[startNode].id, vertices[finishNode].id));
     res.push(vertices[finishNode]);
     
     return res;
diff --git a/script/texts.js b/script/texts.js
index b921593..312b91f 100644
--- a/script/texts.js
+++ b/script/texts.js
@@ -104,6 +104,9 @@ var g_vertexDraw     = "Vertex draw style";
 var g_edgeDraw       = "Edge draw style";
 var g_backgroundStyle = "Bacgkround style";
 
+var g_GrapsIsMultiMessage   = "Graph is multigraph";
+var g_GrapsIsGeneralMessage = "";
+
 function loadTexts()
 {
 	g_textsSelectAndMove  = document.getElementById("SelectAndMoveObject").innerHTML;
@@ -208,4 +211,7 @@ function loadTexts()
     g_edgeDraw   = document.getElementById("edgeDrawStyle").innerHTML;
     
     g_backgroundStyle = document.getElementById("backgroundStyle").innerHTML;
+    
+    g_GrapsIsMultiMessage   = document.getElementById("graphIsMultiMessage").innerHTML;
+    g_GrapsIsGeneralMessage = document.getElementById("graphIsGeneralMessage").innerHTML;
 }
diff --git a/tpl/home.php b/tpl/home.php
index 632f1a5..a767eba 100755
--- a/tpl/home.php
+++ b/tpl/home.php
@@ -150,6 +150,7 @@
     </section>
 
     <section id="canvasSection">
+    <span id="CanvasMessage"></span>    
     <button type="button" class="btn btn-default btn-sm hidden-phone" id="Fullscreen"><span class="glyphicon glyphicon-resize-full fa-fw" id="FullscreenIcon"></span></button>
 	<canvas id="canvas"><?= L('browser_no_support')?></canvas>
     <div id="developerTools" class="well well-sm">
@@ -221,6 +222,20 @@
 			  <span onClick="document.getElementById('EdgeWeight').value='7'; document.getElementById('EdgeWeightSlider').value=7;" style="cursor: pointer"  class="defaultWeigth">7</span>
 			  <span onClick="document.getElementById('EdgeWeight').value='11'; document.getElementById('EdgeWeightSlider').value=11;" style="cursor: pointer"  class="defaultWeigth">11</span>
 			  </div>
+              <div id="NewEdgeAction">
+                <div class="InlineStyle PaddingRight">
+                  <input class="form-check-input" type="radio" name="NewEdgeActionValue" id="RadiosReplaceEdge" value="replace" checked>
+                  <label for="RadiosReplaceEdge">
+                    <?= L('replace_edge')?>
+                  </label>
+                </div>
+                <div class="InlineStyle PaddingRight">
+                  <input class="form-check-input" type="radio" name="NewEdgeActionValue" id="RadiosAddEdge" value="add">
+                  <label for="RadiosAddEdge" id="RadiosAddEdgeLabel">
+                    <?= L('add_edge')?>
+                  </label>
+                </div>
+              </div>
 		</fieldset>
 		</form>
     </div>
@@ -248,6 +263,7 @@
 		<form>
 		<fieldset>
 				<p><?= L('adjacency_matrix_description')?></p>
+                <p id="AdjacencyMatrixMultiGraphDesc"><?= L('adjacency_matrix_multigraph_description')?></p>
 				<textarea name="adjacencyMatrixField" id="AdjacencyMatrixField" wrap="off"></textarea>
 				<p id="BadMatrixFormatMessage"><?= L('adjacency_matrix_bad_format')?></p>
 		</fieldset>
@@ -551,7 +567,9 @@
     <p id="edgeDrawStyle" class="translation"><?= L('edge_draw_style')?></p>
     <p id="backgroundStyle" class="translation"><?= L('background_style')?></p>
         
-
+    <p id="graphIsMultiMessage" class="translation"><?= L('graph_is_multi_message')?></p>
+    <p id="graphIsGeneralMessage" class="translation"><?= L('graph_is_general_message')?></p>
+        
 </section>
 <!--
 <script>