diff --git a/extensions/cornerstone/src/index.js b/extensions/cornerstone/src/index.js
index 0d30d2232..985663238 100644
--- a/extensions/cornerstone/src/index.js
+++ b/extensions/cornerstone/src/index.js
@@ -23,7 +23,7 @@ export default {
   /**
    * Only required property. Should be a unique value across all extensions.
    */
-  id: 'cornerstone',
+  id: 'org.ohif.cornerstone',
 
   /**
    *
@@ -39,10 +39,14 @@ export default {
       const onNewImageHandler = jumpData => {
         commandsManager.runCommand('jumpToImage', jumpData);
       };
-      return <OHIFCornerstoneViewport {...props} onNewImage={onNewImageHandler} />;
+      return (
+        <OHIFCornerstoneViewport {...props} onNewImage={onNewImageHandler} />
+      );
     };
 
-    return ExtendedOHIFCornerstoneViewport;
+    return [
+      { name: 'cornerstone', component: ExtendedOHIFCornerstoneViewport },
+    ];
   },
   getToolbarModule() {
     return toolbarModule;
diff --git a/extensions/cornerstone/src/init.js b/extensions/cornerstone/src/init.js
index e2f807838..27e962b80 100644
--- a/extensions/cornerstone/src/init.js
+++ b/extensions/cornerstone/src/init.js
@@ -15,8 +15,6 @@ import measurementServiceMappingsFactory from './utils/measurementServiceMapping
 export default function init({ servicesManager, configuration }) {
   const { UIDialogService, MeasurementService } = servicesManager.services;
 
-  debugger;
-
   const callInputDialog = (data, event, callback) => {
     if (UIDialogService) {
       let dialogId = UIDialogService.create({
diff --git a/extensions/default/src/DicomWebDataSource/index.js b/extensions/default/src/DicomWebDataSource/index.js
index 74f7aa44a..e4c8f9dc9 100644
--- a/extensions/default/src/DicomWebDataSource/index.js
+++ b/extensions/default/src/DicomWebDataSource/index.js
@@ -165,8 +165,6 @@ function createDicomWebApi(dicomWebConfig) {
         }
       });
 
-      debugger;
-
       return imageIds;
     },
   });
diff --git a/modes/example/src/index.js b/modes/example/src/index.js
index fd48b5e58..706d0ca11 100644
--- a/modes/example/src/index.js
+++ b/modes/example/src/index.js
@@ -12,12 +12,25 @@ export default function mode({ modeConfiguration }) {
     routes: [
       {
         path: 'viewer',
-        preInit: ({ toolbarManager }) => {
-          toolbarManager &&
-            toolbarManager.setDefaultLoadOut([
-              [], // Primary
-              [], // Secondary
-            ]);
+        init: ({ toolbarManager }) => {
+          toolbarManager.addButtons([
+            {
+              id: 'StackScroll', // If id not given will use default in button definition.
+              namespace: 'org.ohif.cornerstone.toolbarModule.StackScroll',
+            },
+            {
+              id: 'Zoom',
+              namespace: 'org.ohif.cornerstone.toolbarModule.Zoom',
+            },
+          ]);
+
+          // Could import layout selector here from org.ohif.default (when it exists!)
+          toolbarManager.setToolBarLayout([
+            // Primary
+            ['StackScroll', { label: 'More', subMenu: ['Zoom'] }],
+            // Secondary
+            ['StackScroll'],
+          ]);
         },
         layoutTemplate: ({ routeProps }) => {
           return {
diff --git a/platform/core/src/ToolBarManager.js b/platform/core/src/ToolBarManager.js
new file mode 100644
index 000000000..d94b1488c
--- /dev/null
+++ b/platform/core/src/ToolBarManager.js
@@ -0,0 +1,55 @@
+export default class toolBarManager {
+  constructor(extensionManager) {
+    this.toolBarLayout = [];
+    this.buttons = {};
+    this.extensionManager = extensionManager;
+  }
+
+  addButtons(buttons) {
+    buttons.forEach(button => {
+      const buttonDefinition = this.extensionManager.getModuleEntry(
+        button.namespace
+      );
+
+      const id = button.id || buttonDefinition.id;
+
+      this.buttons[id] = buttonDefinition;
+    });
+
+    console.log(this.buttons);
+  }
+
+  setToolBarLayout(layouts) {
+    const toolBarLayout = [];
+
+    layouts.forEach(layout => {
+      const toolBarDefinitions = [];
+
+      layout.forEach(element => {
+        if (typeof element === 'object') {
+          // process submenu.
+
+          const subMenuDefinition = { label: element.label, subMenu: [] };
+
+          element.subMenu.forEach(subMenuElement => {
+            const button = this.buttons[subMenuElement];
+
+            subMenuDefinition.subMenu.push(button);
+          });
+
+          toolBarDefinitions.push(subMenuDefinition);
+        } else {
+          const button = this.buttons[element];
+
+          toolBarDefinitions.push(button);
+        }
+      });
+
+      toolBarLayout.push(toolBarDefinitions);
+    });
+
+    this.toolBarLayout = toolBarLayout;
+
+    console.log(this.toolBarLayout);
+  }
+}
diff --git a/platform/core/src/extensions/ExtensionManager.js b/platform/core/src/extensions/ExtensionManager.js
index 5fab3d8f3..27b0f2b44 100644
--- a/platform/core/src/extensions/ExtensionManager.js
+++ b/platform/core/src/extensions/ExtensionManager.js
@@ -17,6 +17,9 @@ export default class ExtensionManager {
       this.modules[moduleType] = [];
     });
     this.dataSourceMap = {};
+
+    console.log('modules map');
+    console.log(this.modulesMap);
   }
 
   /**
@@ -55,11 +58,9 @@ export default class ExtensionManager {
     let extensionId = extension.id;
 
     if (!extensionId) {
-      extensionId = Math.random()
-        .toString(36)
-        .substr(2, 5);
-
-      log.warn(`Extension ID not set. Using random string ID: ${extensionId}`);
+      // Note: Mode framework cannot function without IDs.
+      log.warn(extension);
+      throw new Error(`Extension ID not set`);
     }
 
     if (this.registeredExtensionIds.includes(extensionId)) {
@@ -89,25 +90,43 @@ export default class ExtensionManager {
       );
 
       if (extensionModule) {
-        this._initSpecialModuleTypes(
-          extensionId,
-          moduleType,
-          extensionModule,
-          dataSources
-        );
+        switch (moduleType) {
+          case MODULE_TYPES.COMMANDS:
+            this._initCommandsModule(extensionModule);
+            break;
+          case MODULE_TYPES.DATA_SOURCE:
+            this._initDataSourcesModule(
+              extensionModule,
+              extensionId,
+              dataSources
+            );
+            break;
+          case MODULE_TYPES.TOOLBAR:
+            this._initToolBarModule(extensionModule, extensionId);
+            break;
+
+          case MODULE_TYPES.PANEL:
+          case MODULE_TYPES.SOP_CLASS_HANDLER:
+          case MODULE_TYPES.VIEWPORT:
+          case MODULE_TYPES.CONTEXT:
+          case MODULE_TYPES.LAYOUT_TEMPLATE:
+            // Default for most extension points,
+            // Just adds each entry ready for consumption by mode.
+            if (!extensionModule.forEach) {
+              debugger;
+            }
+
+            extensionModule.forEach(element => {
+              this.modulesMap[
+                `${extensionId}.${moduleType}.${element.name}`
+              ] = element;
+            });
+        }
 
         this.modules[moduleType].push({
           extensionId,
           module: extensionModule,
         });
-
-        // TODO -> deal with command modules.
-
-        extensionModule.forEach(element => {
-          this.modulesMap[
-            `${extensionId}.${moduleType}.${element.name}`
-          ] = element;
-        });
       }
     });
 
@@ -124,6 +143,27 @@ export default class ExtensionManager {
     return this.dataSourceMap[dataSourceName];
   };
 
+  _initToolBarModule = (extensionModule, extensionId) => {
+    let { definitions, defaultContext } = extensionModule;
+    if (!definitions || Object.keys(definitions).length === 0) {
+      log.warn('Commands Module contains no command definitions');
+      return;
+    }
+
+    defaultContext = defaultContext || 'VIEWER';
+
+    definitions.forEach(definition => {
+      console.log(`${extensionId}.${MODULE_TYPES.TOOLBAR}.${definition.id}`);
+
+      // TODO -> Deep copy instead of mutation? We only do this once, but would be better.
+      definition.context = definition.context || defaultContext;
+
+      this.modulesMap[
+        `${extensionId}.${MODULE_TYPES.TOOLBAR}.${definition.id}`
+      ] = definition;
+    });
+  };
+
   /**
    * @private
    * @param {string} moduleType
@@ -162,64 +202,52 @@ export default class ExtensionManager {
     }
   };
 
-  _initSpecialModuleTypes = (
-    extensionId,
-    moduleType,
-    extensionModule,
-    dataSources
-  ) => {
-    switch (moduleType) {
-      case 'commandsModule': {
-        const { definitions, defaultContext } = extensionModule;
-        if (!definitions || Object.keys(definitions).length === 0) {
-          log.warn('Commands Module contains no command definitions');
-          return;
+  _initDataSourcesModule(extensionModule, extensionId, dataSources) {
+    extensionModule.forEach(element => {
+      const namespace = `${extensionId}.${MODULE_TYPES.DATA_SOURCE}.${element.name}`;
+
+      dataSources.forEach(dataSource => {
+        if (dataSource.namespace === namespace) {
+          const dataSourceInstance = element.createDataSource(
+            dataSource.configuration
+          );
+
+          if (this.dataSourceMap[dataSource.sourceName]) {
+            this.dataSourceMap[dataSource.sourceName].push(dataSourceInstance);
+          } else {
+            this.dataSourceMap[dataSource.sourceName] = [dataSourceInstance];
+          }
         }
-        this._initCommandsModule(definitions, defaultContext);
-        break;
-      }
-      case 'dataSourcesModule': {
-        extensionModule.forEach(element => {
-          const namespace = `${extensionId}.${moduleType}.${element.name}`;
+      });
+    });
 
-          dataSources.forEach(dataSource => {
-            if (dataSource.namespace === namespace) {
-              const dataSourceInstance = element.createDataSource(
-                dataSource.configuration
-              );
-
-              if (this.dataSourceMap[dataSource.sourceName]) {
-                this.dataSourceMap[dataSource.sourceName].push(
-                  dataSourceInstance
-                );
-              } else {
-                this.dataSourceMap[dataSource.sourceName] = [
-                  dataSourceInstance,
-                ];
-              }
-            }
-          });
-        });
-
-        break;
-      }
-      default:
-      // code block
-    }
-  };
+    extensionModule.forEach(element => {
+      this.modulesMap[
+        `${extensionId}.${MODULE_TYPES.DATA_SOURCE}.${element.name}`
+      ] = element;
+    });
+  }
 
   /**
    *
    * @private
    * @param {Object[]} commandDefinitions
    */
-  _initCommandsModule = (commandDefinitions, defaultContext = 'VIEWER') => {
+  _initCommandsModule = extensionModule => {
+    let { definitions, defaultContext } = extensionModule;
+    if (!definitions || Object.keys(definitions).length === 0) {
+      log.warn('Commands Module contains no command definitions');
+      return;
+    }
+
+    defaultContext = defaultContext || 'VIEWER';
+
     if (!this._commandsManager.getContext(defaultContext)) {
       this._commandsManager.createContext(defaultContext);
     }
 
-    Object.keys(commandDefinitions).forEach(commandName => {
-      const commandDefinition = commandDefinitions[commandName];
+    Object.keys(definitions).forEach(commandName => {
+      const commandDefinition = definitions[commandName];
       const commandHasContextThatDoesNotExist =
         commandDefinition.context &&
         !this._commandsManager.getContext(commandDefinition.context);
diff --git a/platform/core/src/index.js b/platform/core/src/index.js
index 6d4c691e1..296d91b6d 100644
--- a/platform/core/src/index.js
+++ b/platform/core/src/index.js
@@ -20,6 +20,7 @@ import ui from './ui';
 import user from './user.js';
 import dicomMetadataStore from './dicomMetadataStore';
 import displaySetManager from './displaySetManager';
+import ToolBarManager from './ToolBarManager';
 import utils, { hotkeys } from './utils/';
 
 import {
@@ -68,6 +69,7 @@ const OHIF = {
   IWebApiDataSource,
   dicomMetadataStore,
   displaySetManager,
+  ToolBarManager,
 };
 
 export {
@@ -105,6 +107,7 @@ export {
   IWebApiDataSource,
   dicomMetadataStore,
   displaySetManager,
+  ToolBarManager,
 };
 
 export { OHIF };
diff --git a/platform/viewer/src/appInit.js b/platform/viewer/src/appInit.js
index d489808b3..508c34dc7 100644
--- a/platform/viewer/src/appInit.js
+++ b/platform/viewer/src/appInit.js
@@ -47,8 +47,6 @@ function appInit(appConfigOrFunc, defaultExtensions) {
     MeasurementService,
   ]);
 
-  debugger;
-
   /**
    * Example: [ext1, ext2, ext3]
    * Example2: [[ext1, config], ext2, [ext3, config]]
diff --git a/platform/viewer/src/routes/ModeRoute.js b/platform/viewer/src/routes/ModeRoute.js
index 5feacb448..b17848324 100644
--- a/platform/viewer/src/routes/ModeRoute.js
+++ b/platform/viewer/src/routes/ModeRoute.js
@@ -1,5 +1,5 @@
 import React, { useContext, useEffect, useCallback } from 'react';
-import { displaySetManager } from '@ohif/core';
+import { displaySetManager, ToolBarManager } from '@ohif/core';
 import ViewModelContext from './ViewModelContext';
 import Compose from './Compose';
 
@@ -9,15 +9,21 @@ export default function ModeRoute({
   dataSourceName,
   extensionManager,
 }) {
-  const { routes, sopClassHandlers, extensions } = mode;
+  const { routes, sopClassHandlers, extensions, init } = mode;
   const dataSources = extensionManager.getDataSources(dataSourceName);
 
+  const toolbarManager = new ToolBarManager(extensionManager);
+
   // TODO: For now assume one unique datasource.
 
   const dataSource = dataSources[0];
+  const route = routes[0];
+
+  route.init({ toolbarManager });
 
   console.log(dataSource);
 
+  // Add toolbar state to the view model context?
   const { displaySetInstanceUids, setDisplaySetInstanceUids } = useContext(
     ViewModelContext
   );
@@ -42,11 +48,9 @@ export default function ModeRoute({
     createDisplaySets();
   }, [mode, dataSourceName, location]);
 
-  // Deal with toolbar.
-
   // Only handling one route per mode for now
   // You can test via http://localhost:3000/example-mode/dicomweb
-  const layoutTemplateData = routes[0].layoutTemplate({ location });
+  const layoutTemplateData = route.layoutTemplate({ location });
   const layoutTemplateModuleEntry = extensionManager.getModuleEntry(
     layoutTemplateData.id
   );