diff -r aae670254c49 -r 88e8673aaeeb client/js/renderer/noderepr.js
--- a/client/js/renderer/noderepr.js	Wed May 20 10:36:37 2015 +0200
+++ b/client/js/renderer/noderepr.js	Wed May 20 10:39:35 2015 +0200
@@ -17,6 +17,8 @@
             this.renderer.node_layer.activate();
             this.type = "Node";
             this.buildShape();
+            this.hidden = false;
+            this.ghost= false;
             if (this.options.show_node_circles) {
                 this.circle.strokeWidth = this.options.node_stroke_width;
                 this.h_ratio = 1;
@@ -30,6 +32,7 @@
                 this.normal_buttons = [
                                        new Renderer.NodeEditButton(this.renderer, null),
                                        new Renderer.NodeRemoveButton(this.renderer, null),
+                                       new Renderer.NodeHideButton(this.renderer, null),
                                        new Renderer.NodeLinkButton(this.renderer, null),
                                        new Renderer.NodeEnlargeButton(this.renderer, null),
                                        new Renderer.NodeShrinkButton(this.renderer, null)
@@ -97,7 +100,7 @@
             this.last_circle_radius = this.circle_radius;
 
             var old_act_btn = this.active_buttons;
-
+            
             var opacity = 1;
             if (this.model.get("delete_scheduled")) {
                 opacity = 0.5;
@@ -108,8 +111,7 @@
                 this.active_buttons = this.normal_buttons;
                 this.circle.dashArray = null;
             }
-
-            if (this.selected && this.renderer.isEditable()) {
+            if (this.selected && this.renderer.isEditable() && !this.ghost) {
                 if (old_act_btn !== this.active_buttons) {
                     old_act_btn.forEach(function(b) {
                         b.hide();
@@ -136,7 +138,6 @@
             } else {
                 this.title.text(_text);
             }
-
             this.title.css({
                 left: this.paper_coords.x,
                 top: this.paper_coords.y + this.circle_radius * this.h_ratio + this.options.node_label_distance,
@@ -160,7 +161,8 @@
                 this.node_image.remove();
                 delete this.node_image;
             }
-
+            
+            
             if (this.renderer.minimap) {
                 this.minimap_circle.fillColor = _color;
                 var minipos = this.renderer.toMinimapCoords(_model_coords),
@@ -185,7 +187,11 @@
                         }
                 );
             }
-
+            if (this.ghost){
+                this.show(true);
+            } else {
+                if (this.hidden) { this.hide(); }
+            }
         },
         showImage: function() {
             var _image = null;
@@ -336,7 +342,7 @@
         select: function() {
             this.selected = true;
             this.circle.strokeWidth = this.options.selected_node_stroke_width;
-            if (this.renderer.isEditable()) {
+            if (this.renderer.isEditable() && !this.hidden) {
                 this.active_buttons.forEach(function(b) {
                     b.show();
                 });
@@ -358,6 +364,10 @@
                 this.minimap_circle.strokeWidth = this.options.minimap_highlight_weight;
                 this.minimap_circle.strokeColor = this.options.minimap_highlight_color;
             }
+            //if the node is hidden and the mouse hover it, it appears as a ghost
+            if (this.hidden){
+                this.show(true);
+            }
             this._super("select");
         },
         hideButtons: function() {
@@ -376,9 +386,69 @@
                 if (this.renderer.minimap) {
                     this.minimap_circle.strokeColor = undefined;
                 }
+                //when the mouse don't hover the node anymore, we hide it
+                if (this.hidden){
+                    this.hide();
+                }
                 this._super("unselect");
             }
         },
+        hide: function(){
+            var _this = this;
+            this.ghost = false;
+            this.hidden = true;
+            if (typeof this.node_image !== 'undefined'){
+                this.node_image.opacity = 0;                
+            }
+            this.hideButtons();
+            this.circle.opacity = 0;
+            this.title.css('opacity', 0);
+            this.minimap_circle.opacity = 0;
+            
+            
+            _.each(
+                    this.project.get("edges").filter(
+                            function (ed) {
+                                return ((ed.get("to") === _this.model) || (ed.get("from") === _this.model));
+                            }
+                    ),
+                    function(edge, index, list) {
+                        var repr = _this.renderer.getRepresentationByModel(edge);
+                        if (repr && typeof repr.from_representation !== "undefined" && typeof repr.from_representation.paper_coords !== "undefined" && typeof repr.to_representation !== "undefined" && typeof repr.to_representation.paper_coords !== "undefined") {
+                            repr.hide();
+                        }
+                    }
+            );
+        },
+        show: function(ghost){
+            var _this = this;
+            this.ghost = ghost;
+            if (this.ghost){
+                if (typeof this.node_image !== 'undefined'){
+                    this.node_image.opacity = 0.3;
+                }
+                this.circle.opacity = 0.3;
+                this.title.css('opacity', 0.3);
+                this.minimap_circle.opacity = 0.3;
+            } else {
+                this.hidden = false;
+                this.redraw();
+            }
+            
+            _.each(
+                    this.project.get("edges").filter(
+                            function (ed) {
+                                return ((ed.get("to") === _this.model) || (ed.get("from") === _this.model));
+                            }
+                    ),
+                    function(edge, index, list) {
+                        var repr = _this.renderer.getRepresentationByModel(edge);
+                        if (repr && typeof repr.from_representation !== "undefined" && typeof repr.from_representation.paper_coords !== "undefined" && typeof repr.to_representation !== "undefined" && typeof repr.to_representation.paper_coords !== "undefined") {
+                            repr.show(_this.ghost);
+                        }
+                    }
+            );            
+        },
         highlight: function(textToReplace) {
             var hlvalue = textToReplace || true;
             if (this.highlighted === hlvalue) {
@@ -418,10 +488,19 @@
             if (this.renderer.is_dragging && this.renderer.isEditable()) {
                 this.saveCoords();
             } else {
-                if (!_isTouch && !this.model.get("delete_scheduled")) {
-                    this.openEditor();
+                if (this.hidden){
+                    var index = this.renderer.hiddenNodes.indexOf(this.model.id);
+                    if (index !== -1){
+                        this.renderer.hiddenNodes.splice(index, 1);
+                    }
+                    this.show(false);
+                    this.select();
+                }else{
+                    if (!_isTouch && !this.model.get("delete_scheduled")) {
+                        this.openEditor();
+                    }
+                    this.model.trigger("clicked");                    
                 }
-                this.model.trigger("clicked");
             }
             this.renderer.click_target = null;
             this.renderer.is_dragging = false;