diff --git a/src/demo/app/app.component.html b/src/demo/app/app.component.html
index 662b0df..76b980b 100644
--- a/src/demo/app/app.component.html
+++ b/src/demo/app/app.component.html
@@ -7,7 +7,7 @@
   Spring Flo Sample
 </div>
 <div id="flo-container">
-  <flo-editor (floApi)="editorContext = $event" [metamodel]="metamodel" [renderer]="renderer" [editor]="editor" [paletteSize]="paletteSize" [(dsl)]="dsl" [paperPadding]="20" (validationMarkers)="markersChanged($event)">
+  <flo-editor (floApi)="editorContext = $event" [metamodel]="metamodel" [renderer]="renderer" [editor]="editor" [paletteSize]="paletteSize" [paletteEntryPadding]="{width: 4, height: 4}" [(dsl)]="dsl" [paperPadding]="20" (validationMarkers)="markersChanged($event)">
       <div id="controls" class="controls">
         <button class="button" id="clearGraph" (click)="editorContext.clearGraph()">Create New Flow</button>
         <!-- let's use the 'x' control on the nodes themselves when they are selected
diff --git a/src/demo/app/editor.ts b/src/demo/app/editor.ts
index b1dcd74..bb05551 100644
--- a/src/demo/app/editor.ts
+++ b/src/demo/app/editor.ts
@@ -27,6 +27,23 @@ const joint : any = Flo.joint;
  */
 export class Editor implements Flo.Editor {
 
+    get highlighting() {
+      return {
+        connecting: {
+          name: 'addParentClass',
+          options: {
+            className: 'connecting'
+          }
+        },
+        'default': {
+          name: 'addClass',
+          options: {
+            className: 'highlighted'
+          }
+        }
+      };
+    }
+
     constructor(private modelService : BsModalService) {}
 
     createHandles(context : Flo.EditorContext, createHandle : (owner : dia.CellView, kind : string, action : () => void, location : dia.Point) => void, owner : dia.CellView) {
diff --git a/src/demo/app/metamodel.ts b/src/demo/app/metamodel.ts
index 9744d0c..7a4567b 100644
--- a/src/demo/app/metamodel.ts
+++ b/src/demo/app/metamodel.ts
@@ -29,6 +29,11 @@ const metamodelData: Array<RawMetadata> = [{
     {id: 'withSubDir', name: 'withSubDir', description: 'With subdirectories', defaultValue: true, type: 'boolean'},
     {id: 'type', name: 'type', description: 'Type of file watching', type: 'enum', options: ['tough', 'so-so', 'easy']}
   ],
+}, {
+  name: 'multi', group: 'processor', description: 'Custom element with multiple inputs and outputs',
+  properties: [
+    {id: 'inputChannel', name: 'input-channel', description: 'input channel name', type: 'string'}
+  ],
 }, {
   name: 'transform', group: 'processor', description: 'Apply an expression to modify incoming messages',
   properties: [
diff --git a/src/demo/app/renderer.ts b/src/demo/app/renderer.ts
index d51e359..a6d11d2 100644
--- a/src/demo/app/renderer.ts
+++ b/src/demo/app/renderer.ts
@@ -29,6 +29,234 @@ const HANDLE_ICON_MAP = new Map<string, string>()
 const DECORATION_ICON_MAP = new Map<string, string>()
   .set(Constants.ERROR_DECORATION_KIND, 'icons/error.svg');
 
+const IMAGE_W = 120;
+const IMAGE_H = 40;
+
+const PORT_RADIUS = 2;
+
+joint.shapes.flo.Multi = joint.shapes.basic.Generic.extend({
+
+  markup:
+  '<g class="stream-module">' +
+  '<g class="shape">' +
+  '<rect class="box"/>' +
+  '<text class="label"/>' +
+  '<text class="label2"/>' +
+  '</g>' +
+  '<g class="port1-group">' +
+    '<circle class="input-port1" />' +
+    '<g class="label-group">' +
+      '<rect class="port1-label-rect"/>' +
+      '<text class="port1-label"></text>' +
+    '</g>' +
+  '</g>' +
+  '<g class="port2-group">' +
+    '<circle class="input-port2" />' +
+    '<g class="label-group">' +
+      '<rect class="port2-label-rect"/>' +
+      '<text class="port2-label"></text>' +
+    '</g>' +
+  '</g>' +
+  '<g class="port3-group">' +
+    '<circle class="input-port3" />' +
+    '<g class="label-group">' +
+      '<rect class="port3-label-rect"/>' +
+      '<text class="port3-label"></text>' +
+    '</g>' +
+  '</g>' +
+  '<g class="port4-group">' +
+    '<circle class="input-port4" />' +
+    '<g class="label-group">' +
+      '<rect class="port4-label-rect"/>' +
+      '<text class="port4-label"></text>' +
+    '</g>' +
+  '</g>' +
+  '<g class="port5-group">' +
+    '<circle class="input-port5" />' +
+    '<g class="label-group">' +
+      '<rect class="port5-label-rect"/>' +
+      '<text class="port5-label"></text>' +
+    '</g>' +
+  '</g>' +
+  '<rect class="output-port"/>' +
+  '</g>',
+
+  defaults: joint.util.defaultsDeep({
+
+    type: joint.shapes.flo.NODE_TYPE,
+    position: {x: 0, y: 0},
+    size: { width: IMAGE_W, height: IMAGE_H },
+    attrs: {
+      '.': {
+        magnet: false,
+      },
+      '.box': {
+        width: IMAGE_W,
+        height: IMAGE_H,
+        rx: 2,
+        ry: 2,
+        // 'fill-opacity':0, // see through
+        stroke: '#6db33f',
+        fill: '#eeeeee',
+        'stroke-width': 2,
+      },
+      '.input-port1': {
+        id: 'in-port-1',
+        port: 'input',
+        ref: '.box',
+        refCx: 0,
+        refCy: 1 * 0.17,
+        r: PORT_RADIUS,
+        magnet: true,
+        class: 'input-port1 flo-input-port'
+      },
+      '.port1-label': {
+        ref: '.input-port1',
+        'ref-x': 10,
+        'ref-y': 0,
+        text: 'port-1',
+        class: 'port1-label flo-port-label'
+      },
+      '.port1-label-rect': {
+        ref: '.port1-label',
+        refWidth: 1,
+        refHeight: 1,
+        refX: 0,
+        refY: 0,
+        class: 'port1-label-rect flo-port-label-bg'
+      },
+      '.input-port2': {
+        id: 'in-port-2',
+        port: 'in-port-2',
+        r: PORT_RADIUS,
+        ref: '.box',
+        refCx: 0,
+        refCy: 2 * 0.17,
+        magnet: true,
+        class: 'input-port2 flo-input-port'
+      },
+      '.port2-label': {
+        ref: '.input-port2',
+        'ref-x': 10,
+        'ref-y': 0,
+        text: 'port-2',
+        class: 'port2-label flo-port-label'
+      },
+      '.port2-label-rect': {
+        ref: '.port2-label',
+        refWidth: 1,
+        refHeight: 1,
+        refX: 0,
+        refY: 0,
+        class: 'port2-label-rect flo-port-label-bg'
+      },
+      '.input-port3': {
+        id: 'in-port-3',
+        port: 'input',
+        r: PORT_RADIUS,
+        ref: '.box',
+        refCx: 0,
+        refCy: 3 * 0.17,
+        magnet: true,
+        class: 'input-port3 flo-input-port'
+      },
+      '.port3-label': {
+        ref: '.input-port3',
+        'ref-x': 10,
+        'ref-y': 0,
+        text: 'port-3',
+        class: 'port3-label flo-port-label'
+      },
+      '.port3-label-rect': {
+        ref: '.port3-label',
+        refWidth: 1,
+        refHeight: 1,
+        refX: 0,
+        refY: 0,
+        class: 'port3-label-rect flo-port-label-bg'
+      },
+      '.input-port4': {
+        id: 'in-port-4',
+        port: 'input',
+        r: PORT_RADIUS,
+        ref: '.box',
+        refCx: 0,
+        refCy: 4 * 0.17,
+        magnet: true,
+        class: 'input-port4 flo-input-port'
+      },
+      '.port4-label': {
+        ref: '.input-port4',
+        'ref-x': 10,
+        'ref-y': 0,
+        text: 'port-4',
+        class: 'port4-label flo-port-label'
+      },
+      '.port4-label-rect': {
+        ref: '.port4-label',
+        refWidth: 1,
+        refHeight: 1,
+        refX: 0,
+        refY: 0,
+        class: 'port4-label-rect flo-port-label-bg'
+      },
+      '.input-port5': {
+        id: 'in-port-5',
+        port: 'input',
+        r: PORT_RADIUS,
+        ref: '.box',
+        refCx: 0,
+        refCy: 5 * 0.17,
+        magnet: true,
+        class: 'input-port5 flo-input-port'
+      },
+      '.port5-label': {
+        ref: '.input-port5',
+        'ref-x': 10,
+        'ref-y': 0,
+        text: 'port-5',
+        class: 'port5-label flo-port-label'
+      },
+      '.port5-label-rect': {
+        ref: '.port5-label',
+        refWidth: 1,
+        refHeight: 1,
+        refX: 0,
+        refY: 0,
+        class: 'port5-label-rect flo-port-label-bg'
+      },
+      '.output-port': {
+        port: 'output',
+        height: 8, width: 8,
+        magnet: true,
+        fill: '#eeeeee',
+        transform: 'translate(' + (IMAGE_W - 4) + ',' + ((IMAGE_H / 2) - 4) + ')',
+        stroke: '#34302d',
+        'stroke-width': 1,
+      },
+      '.label': {
+        'ref-x': 0.5, // jointjs specific: relative position to ref'd element
+        'ref-y': 0.525,
+        'y-alignment': 'middle',
+        'x-alignment': 'middle',
+        ref: '.box', // jointjs specific: element for ref-x, ref-y
+        fill: 'black',
+        'font-size': 14
+      },
+      '.label2': {
+        'y-alignment': 'middle',
+        'ref-x': 0.15, // jointjs specific: relative position to ref'd element
+        'ref-y': 0.2, // jointjs specific: relative position to ref'd element
+        ref: '.box', // jointjs specific: element for ref-x, ref-y
+        fill: 'black',
+        'font-size': 20
+      },
+      '.shape': {
+      }
+    }
+  }, joint.shapes.basic.Generic.prototype.defaults)
+});
+
 /**
  * @author Alex Boyko
  * @author Andy Clement
@@ -46,8 +274,8 @@ export class Renderer implements Flo.Renderer {
       });
     }
 
-    createDecoration(kind : string) : dia.Element {
-      return new joint.shapes.flo.ErrorDecoration({
+    createDecoration(kind : string, parent: dia.Cell) : dia.Element {
+      const error = new joint.shapes.flo.ErrorDecoration({
         size: {width: 16, height: 16},
         attrs: {
           'image': {
@@ -55,9 +283,19 @@ export class Renderer implements Flo.Renderer {
           }
         }
       });
+      if (parent instanceof joint.dia.Element) {
+        const pt = (<dia.Element> parent).getBBox().topRight().offset(-error.size().width, 0);
+        error.position(pt.x, pt.y);
+      } else {
+        // TODO: do something for the link perhaps?
+      }
+      return error;
     }
 
-    createNode(metadata : Flo.ElementMetadata, props : Map<string, any>): dia.Element {
+    createNode(viewerDescriptor: Flo.ViewerDescriptor, metadata : Flo.ElementMetadata, props : Map<string, any>): dia.Element {
+      if (metadata.name === 'multi') {
+        return new joint.shapes.flo.Multi();
+      }
       return new joint.shapes.flo.Node();
     }
 
@@ -76,17 +314,66 @@ export class Renderer implements Flo.Renderer {
     }
 
     createLink(source : Flo.LinkEnd, target : Flo.LinkEnd, metadata : Flo.ElementMetadata, props : Map<string, any>) : dia.Link {
-      return new joint.shapes.flo.Link(joint.util.deepSupplement({
+      const link = new joint.shapes.flo.Link(joint.util.deepSupplement({
         smooth: true,
         attrs: {
           '.': {
             //filter: { name: 'dropShadow', args: { dx: 1, dy: 1, blur: 2 } }
           },
-          '.connection': { 'stroke-width': 3, 'stroke': 'black', 'stroke-linecap': 'round' },
-          '.marker-arrowheads': { display: 'none' },
-          '.tool-options': { display: 'none' }
+          '.connection': {'stroke-width': 3, 'stroke': 'black', 'stroke-linecap': 'round'},
+          '.marker-arrowheads': {display: 'none'},
+          '.tool-options': {display: 'none'}
         },
-      }, joint.shapes.flo.Link.prototype.defaults));
+      }));
+      return link;
+    }
+
+  handleLinkEvent?(context: Flo.EditorContext, event: string, link: dia.Link) {
+      switch (event) {
+        case 'change:target':
+          this.updateTargetLabel(link, context.getPaper());
+          break;
+      }
+  }
+
+  updateTargetLabel(link: joint.dia.Link, paper: dia.Paper) {
+      const view = paper.findViewByModel(link.getTargetElement());
+      const portElement = view ? view.findBySelector(link.target().selector) : undefined;
+      const labelText = portElement && portElement.length ? portElement[0].getAttribute('id') : undefined;
+      setTimeout(() => {
+        let idx = -1;
+        for (let i = 0; idx < 0 && i < link.labels().length; i++) {
+          if (link.labels()[i].attrs.text.id === 'target-channel-label') {
+            idx = i;
+          }
+        }
+        if (idx >= 0) {
+          link.removeLabel(idx);
+        }
+        if (labelText) {
+          link.appendLabel({
+            attrs: {
+              text: {
+                id: 'target-channel-label',
+                text: labelText,
+                class: 'link-channel-label',
+                'text-anchor': 'end'
+              },
+              rect: {
+                class: 'link-channel-label'
+              }
+            },
+            position: {
+              args: {
+                keepGradient: true,
+                ensureLegibility: true
+              },
+              distance: -20,
+              offset: 20
+            },
+          });
+        }
+      });
     }
 
     isSemanticProperty(propertyPath : string, element : dia.Cell) : boolean {
diff --git a/src/demo/styles.css b/src/demo/styles.css
index 6569e4c..8c42ab9 100644
--- a/src/demo/styles.css
+++ b/src/demo/styles.css
@@ -9,3 +9,56 @@ h1 {
   font-family: Arial, Helvetica, sans-serif;
   font-size: 250%;
 }
+
+.connecting .flo-input-port {
+  fill: #aa1111;
+  r: 4;
+}
+
+.connecting .label-group {
+  display: block;
+}
+
+.label-group {
+  display: none;
+}
+
+.flo-input-port {
+  fill: #eeeeee;
+  stroke: #34302d;
+  stroke-width: 1px;
+}
+
+.flo-port-label {
+  text-anchor: start;
+  fill: black;
+}
+
+.flo-port-label-bg {
+  fill: lightblue;
+  stroke: lightblue;
+  stroke-width: 7px;
+  rx: 3;
+  ry: 3;
+  refWidth: 1;
+  refHeight: 1;
+}
+
+.joint-link:hover .link-channel-label {
+  opacity: 1;
+}
+
+.link-channel-label {
+  opacity: 0;
+}
+
+.available-magnet {
+  stroke-width: 2px;
+}
+
+.joint-element.highlighted rect {
+  stroke: #34302d;
+  stroke-width: 3;
+}
+
+