diff --git a/modules/plugable/pluginSystem.ts b/modules/plugable/pluginSystem.ts
index 03f0c2d5..6442c567 100644
--- a/modules/plugable/pluginSystem.ts
+++ b/modules/plugable/pluginSystem.ts
@@ -1,3 +1,4 @@
+import {WizardSelectionContext} from "cad/craft/wizard/wizardSelectionPlugin";
 
 
 type BagOfPlugins = Set<Plugin<any, any>>;
@@ -22,10 +23,11 @@ export class PluginSystem {
     while (needPass) {
       needPass = false;
       this.waitingQueue.forEach(plugin => {
-        const localContext = plugin.readiness(this.globalContext);
-        if (!!localContext) {
+        const ready = readiness(plugin, this.globalContext);
+        if (ready) {
           try  {
-            plugin.activate(localContext);
+            plugin.activate(this.globalContext);
+            checkActivation(plugin, this.globalContext);
             needPass = true;
             this.plugins.add(plugin);
           } catch (error) {
@@ -42,7 +44,9 @@ export class PluginSystem {
     this.waitingQueue.delete(plugin);
     this.plugins.delete(plugin);
     try {
-      plugin.deactivate(this.globalContext);
+      if (plugin.deactivate) {
+        plugin.deactivate(this.globalContext);
+      }
     } catch (error) {
       console.error(error);
     }
@@ -54,8 +58,8 @@ export class PluginSystem {
         if (!plugin.deactivate) {
           return;
         }
-        const localContext = plugin.readiness(this.globalContext);
-        if (!localContext) {
+        const isReady = readiness(plugin, this.globalContext);
+        if (!isReady) {
           try {
             plugin.deactivate(this.globalContext);
             this.plugins.delete(plugin);
@@ -70,13 +74,40 @@ export class PluginSystem {
   }
 }
 
+function readiness(plugin: Plugin<any, any>, globalContext: any) {
+  const specKeys = Object.keys(plugin.inputContextSpec);
+  for (let key of specKeys) {
+    if (!globalContext[key] && plugin.inputContextSpec[key] === 'required') {
+      return false;
+    }
+  }
+  return true;
+}
 
-export interface Plugin<GlobalContext, WorkingContext> {
+function checkActivation(plugin: Plugin<any, any>, globalContext: any) {
+  const specKeys = Object.keys(plugin.outputContextSpec);
+  for (let key of specKeys) {
+    if (!globalContext[key] && plugin.outputContextSpec[key] === 'required') {
+      console.error("declared service was never activated: " + key);
+    }
+  }
+}
 
-  readiness(ctx: GlobalContext): WorkingContext;
+export type Spec = 'required' | 'optional';
 
-  activate(ctx: WorkingContext);
+export type ContextSpec<T> = {
+  [Property in keyof T]: Spec;
+};
 
-  deactivate?(ctx: WorkingContext);
+
+export interface Plugin<InputContext, OutputContext, WorkingContext = InputContext&OutputContext> {
+
+  inputContextSpec: ContextSpec<InputContext>;
+
+  outputContextSpec: ContextSpec<OutputContext>;
+
+  activate(ctx: InputContext&OutputContext);
+
+  deactivate?(ctx: InputContext&OutputContext);
 
 }
diff --git a/modules/ui/components/GenericWizard.tsx b/modules/ui/components/GenericWizard.tsx
index a9830d21..8fa067da 100644
--- a/modules/ui/components/GenericWizard.tsx
+++ b/modules/ui/components/GenericWizard.tsx
@@ -13,7 +13,7 @@ export function GenericWizard({topicId, title, left, className, children, onCanc
   left?: number,
   onCancel: () => any,
   onOK: () => any,
-  onKeyDown: (e) => any,
+  onKeyDown?: (e) => any,
   infoText: any
 } & WindowProps ) {
 
diff --git a/web/app/cad/craft/schema/schema.ts b/web/app/cad/craft/schema/schema.ts
index 3c4e181c..431d00b4 100644
--- a/web/app/cad/craft/schema/schema.ts
+++ b/web/app/cad/craft/schema/schema.ts
@@ -29,7 +29,7 @@ export type OperationFlattenSchema = {
 
 export interface BaseSchemaField {
   defaultValue?: OperationParamValue,
-  optional: boolean,
+  optional?: boolean,
   label?: string,
   resolve?: ValueResolver<any, any>
 }
diff --git a/web/app/cad/craft/wizard/wizardPlugin.ts b/web/app/cad/craft/wizard/wizardPlugin.ts
index ac47ba87..97328a85 100644
--- a/web/app/cad/craft/wizard/wizardPlugin.ts
+++ b/web/app/cad/craft/wizard/wizardPlugin.ts
@@ -1,21 +1,16 @@
 import {combine, state, StateStream} from 'lstream';
-import initializeBySchema, {fillUpMissingFields} from '../schema/initializeBySchema';
+import initializeBySchema from '../schema/initializeBySchema';
 import {clone} from 'gems/objects';
 import materializeParams from '../schema/materializeParams';
 import {createFunctionList} from 'gems/func';
-import {CraftHints, CraftHistory, OperationRequest} from "cad/craft/craftPlugin";
-import {NewOperationCall, ParamsPath, WizardService, WizardState} from "cad/craft/wizard/wizardTypes";
+import {CraftHistory, OperationRequest} from "cad/craft/craftPlugin";
+import {NewOperationCall, ParamsPath, WizardService, WizardState, WorkingRequest} from "cad/craft/wizard/wizardTypes";
 import _ from "lodash";
 import {OperationParamValue} from "cad/craft/schema/schema";
 import {ApplicationContext} from "context";
 import {Operation} from "cad/craft/operationPlugin";
 import produce from "immer"
 
-type WorkingRequest = OperationRequest & {
-  hints?: CraftHints,
-  requestKey: number
-}
-
 export function activate(ctx: ApplicationContext) {
 
   let {streams, services} = ctx;
@@ -85,7 +80,6 @@ export function activate(ctx: ApplicationContext) {
   // reset effect
   workingRequest$.pairwise().attach(([old, curr]) => {
     if (old !== null && old.requestKey !== curr?.requestKey) {
-      console.log("=========> DISPOSE")
       disposerList.call();
       disposerList = createFunctionList();
       state$.next({});
@@ -169,9 +163,12 @@ export function activate(ctx: ApplicationContext) {
   ctx.wizardService = services.wizard = wizardService;
 }
 
+export interface WizardOutputContext {
+  wizardService: WizardService
+}
+
 declare module 'context' {
-  interface ApplicationContext {
-    wizardService: WizardService
+  interface ApplicationContext extends WizardOutputContext {
   }
 }
 
diff --git a/web/app/cad/craft/wizard/wizardSelectionPlugin.ts b/web/app/cad/craft/wizard/wizardSelectionPlugin.ts
index 58b510f8..cab27d43 100644
--- a/web/app/cad/craft/wizard/wizardSelectionPlugin.ts
+++ b/web/app/cad/craft/wizard/wizardSelectionPlugin.ts
@@ -1,43 +1,66 @@
 import {FACE, SHELL} from 'cad/model/entities';
-import {memoize} from "lodash/function";
 import {OperationRequest} from "cad/craft/craftPlugin";
 import {FlattenPath, ParamsPath, WizardService} from "cad/craft/wizard/wizardTypes";
 import {OperationParamValue} from "cad/craft/schema/schema";
 import {EntityReference} from "cad/craft/operationPlugin";
-import {ApplicationContext} from "context";
+import {ContextSpec, Plugin, Spec} from "plugable/pluginSystem";
+import {MarkerPluginOutputContext} from "cad/scene/selectionMarker/markerPlugin";
+import {WizardOutputContext} from "cad/craft/wizard/wizardPlugin";
+import {PickControlOutputContext} from "cad/scene/controls/pickControlPlugin";
 
-export function activate(ctx: ApplicationContext) {
-  const wizardService = ctx.wizardService;
-  wizardService.workingRequest$.attach((opRequest: OperationRequest) => {
-    ctx.services.marker.clear();
-    if (opRequest) {
-      const wizardPickHandler = createPickHandlerFromSchema(wizardService);
-      ctx.services.pickControl.setPickHandler(wizardPickHandler);
-      const marker = ctx.services.marker;
-      marker.startSession();
-      let {schemaIndex} = wizardService.operation;
-      schemaIndex.entities.forEach(entityRef => {
-        //TODO: move to uiDefinition
-        let color = entityRef.metadata.markColor;
+export type WizardSelectionInputContext = MarkerPluginOutputContext & WizardOutputContext & PickControlOutputContext;
 
-        let val = wizardService.readParam(entityRef.field.path);
-
-        if (Array.isArray(val)) {
-          val.forEach(id => marker.mark(id, color));
-        } else {
-          if (val) {
-            marker.mark(val, color);
-          }
-        }
-      });
-      marker.commit();
-
-    } else {
-      ctx.services.pickControl.setPickHandler(null);
-    }
-  });
+export interface WizardSelectionOutputContext {
 }
 
+export type WizardSelectionContext = WizardSelectionInputContext & WizardSelectionOutputContext;
+
+export const WizardSelectionPlugin: Plugin<WizardSelectionInputContext, WizardSelectionOutputContext, WizardSelectionContext> = {
+
+  inputContextSpec: {
+    markerService: 'required',
+    pickControlService: 'required',
+    wizardService: 'required'
+  },
+
+  outputContextSpec: {
+  },
+
+  activate(ctx: WizardSelectionContext) {
+    const wizardService = ctx.wizardService;
+    wizardService.workingRequest$.attach((opRequest: OperationRequest) => {
+      ctx.markerService.clear();
+      if (opRequest) {
+        const wizardPickHandler = createPickHandlerFromSchema(wizardService);
+        ctx.pickControlService.setPickHandler(wizardPickHandler);
+        const marker = ctx.markerService;
+        marker.startSession();
+        let {schemaIndex} = wizardService.operation;
+        schemaIndex.entities.forEach(entityRef => {
+          //TODO: move to uiDefinition
+          let color = entityRef.metadata.markColor;
+
+          let val = wizardService.readParam(entityRef.field.path);
+
+          if (Array.isArray(val)) {
+            val.forEach(id => marker.mark(id, color));
+          } else {
+            if (val) {
+              marker.mark(val, color);
+            }
+          }
+        });
+        marker.commit();
+
+      } else {
+        ctx.pickControlService.setPickHandler(null);
+      }
+    });
+  },
+
+}
+
+
 const singleValue = (id, current) =>  id;
 const arrayValue = (id, arr) =>  {
   if (!arr) {
@@ -49,8 +72,6 @@ const arrayValue = (id, arr) =>  {
   return arr;
 };
 
-const getEntityParams = memoize(schema => Object.keys(schema).filter(key => schema[key].type === 'entity'));
-
 function createPickHandlerFromSchema(wizardService: WizardService) {
 
   function update(param: ParamsPath, value: OperationParamValue, paramToMakeActive: FlattenPath) {
diff --git a/web/app/cad/craft/wizard/wizardTypes.ts b/web/app/cad/craft/wizard/wizardTypes.ts
index 6a052ece..108b064c 100644
--- a/web/app/cad/craft/wizard/wizardTypes.ts
+++ b/web/app/cad/craft/wizard/wizardTypes.ts
@@ -14,9 +14,14 @@ export type WizardState = {
   error?: any
 };
 
+export type WorkingRequest = OperationRequest & {
+  hints?: CraftHints,
+  requestKey: number
+}
+
 export interface WizardService {
 
-  workingRequest$: StateStream<OperationRequest&{hints?: CraftHints}>;
+  workingRequest$: StateStream<WorkingRequest>;
 
   materializedWorkingRequest$: StateStream<MaterializedOperationParams>;
 
diff --git a/web/app/cad/dom/domPlugin.ts b/web/app/cad/dom/domPlugin.ts
index 54ad3a1d..74104643 100644
--- a/web/app/cad/dom/domPlugin.ts
+++ b/web/app/cad/dom/domPlugin.ts
@@ -1,20 +1,6 @@
 import {contributeComponent} from './components/ContributedComponents';
-
-export function activate(ctx) {
-
-  ctx.domService = {
-    viewerContainer: document.getElementById('viewer-container'),
-    contributeComponent
-  };
-
-  ctx.services.dom = ctx.domService;
-
-  ctx.appTabsService.tabs$.attach(({activeTab}) => {
-    if (activeTab === 0) {
-      ctx.services.viewer.sceneSetup.updateViewportSize();
-    }
-  });
-}
+import {Plugin} from "plugable/pluginSystem";
+import {AppTabsService} from "cad/dom/appTabsPlugin";
 
 export interface DomService {
 
@@ -24,12 +10,48 @@ export interface DomService {
 
 }
 
+export interface DomInputContext {
+  appTabsService: AppTabsService;
+  services: any;
+}
+
+export interface DomOutputContext {
+  domService: DomService;
+}
+
+export type DomContext = DomInputContext&DomOutputContext;
+
 declare module 'context' {
-
-  interface ApplicationContext {
-
-    domService: DomService;
-  }
+  interface ApplicationContext extends DomOutputContext {}
+}
+
+
+export const DomPlugin: Plugin<DomInputContext, DomOutputContext, DomContext> = {
+
+  inputContextSpec: {
+    appTabsService: 'required',
+    services: 'required',
+  },
+
+  outputContextSpec: {
+    domService: 'required',
+  },
+
+  activate(ctx: DomInputContext&DomOutputContext) {
+    ctx.domService = {
+      viewerContainer: document.getElementById('viewer-container'),
+      contributeComponent
+    };
+
+    ctx.services.dom = ctx.domService;
+
+    ctx.appTabsService.tabs$.attach(({activeTab}) => {
+      if (activeTab === 0) {
+        ctx.services.viewer.sceneSetup.updateViewportSize();
+      }
+    });
+  },
+
 }
 
 
diff --git a/web/app/cad/init/startApplication.js b/web/app/cad/init/startApplication.js
index 24c4c6e0..d92f8880 100644
--- a/web/app/cad/init/startApplication.js
+++ b/web/app/cad/init/startApplication.js
@@ -1,6 +1,6 @@
 import * as LifecyclePlugin from './lifecyclePlugin';
 import * as AppTabsPlugin from '../dom/appTabsPlugin';
-import * as DomPlugin from '../dom/domPlugin';
+import {DomPlugin} from '../dom/domPlugin';
 import * as PickControlPlugin from '../scene/controls/pickControlPlugin';
 import * as MouseEventSystemPlugin from '../scene/controls/mouseEventSystemPlugin';
 import * as ScenePlugin from '../scene/scenePlugin';
@@ -10,7 +10,7 @@ import * as UiPlugin from '../dom/uiPlugin';
 import * as MenuPlugin from '../dom/menu/menuPlugin';
 import * as KeyboardPlugin from '../keyboard/keyboardPlugin';
 import * as WizardPlugin from '../craft/wizard/wizardPlugin';
-import * as WizardSelectionPlugin from '../craft/wizard/wizardSelectionPlugin';
+import {WizardSelectionPlugin} from '../craft/wizard/wizardSelectionPlugin';
 import * as PreviewPlugin from '../preview/previewPlugin';
 import * as OperationPlugin from '../craft/operationPlugin';
 import * as ExtensionsPlugin from '../craft/extensionsPlugin';
@@ -112,13 +112,15 @@ export function defineStreams(plugins, context) {
 
 function adapter(oldStylePlugin) {
 
-  if (oldStylePlugin.readiness) {
+  if (oldStylePlugin.inputContextSpec) {
     return oldStylePlugin;
   }
 
   return {
 
-    readiness: ctx => ctx,
+    inputContextSpec: {},
+
+    outputContextSpec: {},
 
     activate: oldStylePlugin.activate,
 
diff --git a/web/app/cad/location/LocationDialog.tsx b/web/app/cad/location/LocationDialog.tsx
index 4a405002..a0a1007a 100644
--- a/web/app/cad/location/LocationDialog.tsx
+++ b/web/app/cad/location/LocationDialog.tsx
@@ -79,7 +79,7 @@ export function LocationDialog() {
   };
 
   return <GenericWizard
-    left={15}
+    left={535}
     title='PART LOCATION'
     onClose={close}
     className='location-dialog'
diff --git a/web/app/cad/scene/controls/pickControlPlugin.js b/web/app/cad/scene/controls/pickControlPlugin.ts
similarity index 93%
rename from web/app/cad/scene/controls/pickControlPlugin.js
rename to web/app/cad/scene/controls/pickControlPlugin.ts
index 6b0298c4..55c6ebc6 100644
--- a/web/app/cad/scene/controls/pickControlPlugin.js
+++ b/web/app/cad/scene/controls/pickControlPlugin.ts
@@ -5,6 +5,22 @@ import {LOG_FLAGS} from '../../logFlags';
 import * as vec from 'math/vec';
 import {initRayCastDebug, printRaycastDebugInfo, RayCastDebugInfo} from "./rayCastDebug";
 
+export interface PickControlService {
+  setPickHandler(wizardPickHandler: (model) => boolean)
+
+  deselectAll()
+
+  pick()
+
+  pickFromRay()
+
+  simulatePickFromRay()
+}
+
+export interface PickControlOutputContext {
+  pickControlService: PickControlService;
+}
+
 export const PICK_KIND = {
   FACE: mask.type(1),
   SKETCH: mask.type(2),
@@ -27,9 +43,9 @@ const DEFAULT_SELECTION_MODE = Object.freeze({
 export const ALL_EXCLUDING_SOLID_KINDS = PICK_KIND.FACE | PICK_KIND.SKETCH | PICK_KIND.EDGE | PICK_KIND.DATUM_AXIS | PICK_KIND.LOOP;
 
 export function activate(context) {
-  const {services, streams} = context;
+  const {services} = context;
 
-  const defaultHandler = (model, event, rayCastData) => {
+  const defaultHandler = (model, event, rayCastData?) => {
     if (LOG_FLAGS.PICK) {
       printPickInfo(model, rayCastData);
     }
@@ -150,6 +166,8 @@ export function activate(context) {
     setPickHandler, deselectAll, pick, pickFromRay, simulatePickFromRay
   };
 
+  services.pickControlService = services.pickControl;
+
   if (LOG_FLAGS.PICK) {
     initRayCastDebug();
   }
@@ -216,7 +234,7 @@ export function traversePickResults(event, pickResults, kind, visitor) {
   }
 }
 
-function printPickInfo(model, rayCastData) {
+function printPickInfo(model, rayCastData?) {
   console.log("PICKED MODEL:");
   console.dir(model);
   console.log("PICK RAYCAST INFO:");
diff --git a/web/app/cad/scene/scenePlugin.ts b/web/app/cad/scene/scenePlugin.ts
index 94b6d721..fc6b43f0 100644
--- a/web/app/cad/scene/scenePlugin.ts
+++ b/web/app/cad/scene/scenePlugin.ts
@@ -1,7 +1,7 @@
 import Viewer from './viewer';
 import CadScene from './cadScene';
 import {externalState, stream} from 'lstream';
-import {AppTabsService} from "../dom/appTabsPlugin";
+import {ApplicationContext} from "context";
 
 export function defineStreams({streams, services}) {
   streams.cadScene = {
@@ -10,7 +10,8 @@ export function defineStreams({streams, services}) {
   };
 }
 
-export function activate({streams, services}) {
+export function activate(ctx: ApplicationContext) {
+  const {streams, services} = ctx;
   let {dom} = services;
   
   const onRendered = () => streams.cadScene.sceneRendered.next(); 
@@ -19,8 +20,10 @@ export function activate({streams, services}) {
   
   services.viewer = viewer;
   services.cadScene = new CadScene(viewer.sceneSetup.rootGroup);
-  
-  
+
+  ctx.viewer = viewer;
+  ctx.cadScene = services.cadScene;
+
   // let sketcher3D = new Sketcher3D(dom.viewerContainer);
   // services.viewer.setCameraMode(CAMERA_MODE.ORTHOGRAPHIC);
 
diff --git a/web/app/cad/scene/selectionMarker/markerPlugin.js b/web/app/cad/scene/selectionMarker/markerPlugin.ts
similarity index 85%
rename from web/app/cad/scene/selectionMarker/markerPlugin.js
rename to web/app/cad/scene/selectionMarker/markerPlugin.ts
index d4876103..b3f596ec 100644
--- a/web/app/cad/scene/selectionMarker/markerPlugin.js
+++ b/web/app/cad/scene/selectionMarker/markerPlugin.ts
@@ -1,8 +1,34 @@
 import {OrderedMap} from 'gems/linkedMap';
-import {eventStream} from 'lstream';
+import {eventStream, Stream} from 'lstream';
+import {MObject} from "cad/model/mobject";
+
+export interface MarkerService {
+  clear();
+
+  startSession()
+
+  mark(id: any, color: any)
+
+  commit()
+
+  markExclusively()
+
+  markArrayExclusively()
+
+  markAdding()
+
+  isMarked()
+
+  $markedEntities: Stream<MObject>
+}
+
+export interface MarkerPluginOutputContext {
+  markerService: MarkerService;
+}
 
 export function activate(ctx) {
   ctx.services.marker = createMarker(ctx.services.cadRegistry.find, ctx.services.viewer.requestRender);
+  ctx.markerService = ctx.services.marker;
   ctx.streams.craft.models.attach(() => {
     ctx.services.marker.clear();
   });
diff --git a/web/app/cad/scene/selectionMarker/selectionSynchronizer.js b/web/app/cad/scene/selectionMarker/selectionSynchronizer.js
index 774edbed..fbc11fe6 100644
--- a/web/app/cad/scene/selectionMarker/selectionSynchronizer.js
+++ b/web/app/cad/scene/selectionMarker/selectionSynchronizer.js
@@ -11,7 +11,7 @@ export const selectionSynchronizer = (entity, findEntity, color) => ([old, curr]
   toMark.forEach(id => {
     let model = findEntity(entity, id);
     if (model) {
-      model.ext.view.mark(color);
+      model.ext.view.mark(id, color);
     }
   });
 };
\ No newline at end of file
diff --git a/web/app/cad/workbench/workbenchesLoaderPlugin.ts b/web/app/cad/workbench/workbenchesLoaderPlugin.ts
index e315fd65..31ba7092 100644
--- a/web/app/cad/workbench/workbenchesLoaderPlugin.ts
+++ b/web/app/cad/workbench/workbenchesLoaderPlugin.ts
@@ -1,4 +1,3 @@
-import {ApplicationContext, CoreContext} from "context";
 import {WorkbenchRegistry} from "workbenches/registry";
 import planeOperation from "cad/craft/primitives/simplePlane/simplePlaneOperation";
 import boxOperation from "cad/craft/primitives/box/boxOperation";
@@ -19,37 +18,30 @@ import {intersectionOperation, subtractOperation, unionOperation} from "cad/craf
 import {Plugin} from "plugable/pluginSystem";
 import {WorkbenchService} from "cad/workbench/workbenchService";
 import {OperationService} from "cad/craft/operationPlugin";
-import {checkAllPropsDefined} from "plugable/utils";
 
-export interface WorkbenchesLoaderContext {
+export interface WorkbenchesLoaderInputContext {
   workbenchService: WorkbenchService,
   operationService: OperationService
 }
 
-export const WorkbenchesLoaderPlugin: Plugin<ApplicationContext, WorkbenchesLoaderContext> = {
+export const WorkbenchesLoaderPlugin: Plugin<WorkbenchesLoaderInputContext, {}> = {
 
-  readiness(ctx: ApplicationContext): WorkbenchesLoaderContext {
-
-    const {
-      workbenchService,
-      operationService
-    } = ctx;
-
-    return checkAllPropsDefined({
-      workbenchService,
-      operationService
-    })
+  inputContextSpec: {
+    workbenchService: 'required',
+    operationService: 'required'
   },
 
-  activate(ctx: WorkbenchesLoaderContext) {
+  outputContextSpec: {},
+
+  activate(ctx) {
     registerCoreOperations(ctx);
     WorkbenchRegistry.forEach(wConfig => ctx.workbenchService.registerWorkbench(wConfig));
     ctx.workbenchService.switchToDefaultWorkbench();
-  },
+  }
 
 }
 
-function registerCoreOperations(ctx: WorkbenchesLoaderContext) {
+function registerCoreOperations(ctx: WorkbenchesLoaderInputContext) {
 
   ctx.operationService.registerOperations([
     planeOperation,
@@ -71,5 +63,5 @@ function registerCoreOperations(ctx: WorkbenchesLoaderContext) {
     intersectionOperation,
     subtractOperation,
     unionOperation,
-  ]);
+  ] as any);
 }
\ No newline at end of file