diff --git a/src/app/constant.js b/src/app/constant.js
index a10121ded..96851a76a 100644
--- a/src/app/constant.js
+++ b/src/app/constant.js
@@ -611,9 +611,15 @@ export const LOCAL_ITEM_IDS = {
 /**
  * @since 3.8.0
  */
-
 export const LOGO_GIS3W = 'images/logo_gis3w_156_85.png';
 
+/**
+ * List of Open Layers spatial methods used to find features
+ * 
+ * @since 3.9.0
+ */
+export const SPATIAL_METHODS = ['intersects', 'within'];
+
 export default {
   APP_VERSION,
   API_BASE_URLS,
@@ -637,6 +643,7 @@ export default {
   QUERY_POINT_TOLERANCE,
   SEARCH_ALLVALUE,
   SEARCH_RETURN_TYPES,
+  SPATIAL_METHODS,
   TIMEOUT,
   TOC_LAYERS_INIT_STATUS,
   TOC_THEMES_INIT_STATUS,
diff --git a/src/app/eventbus.js b/src/app/eventbus.js
new file mode 100644
index 000000000..f9dee8024
--- /dev/null
+++ b/src/app/eventbus.js
@@ -0,0 +1,34 @@
+/**
+ * @file common vue instances used to watch object changes or to emit events
+ * 
+ * NB: node.js modules are singletons by default.
+ * 
+ * @see https://medium.com/@lazlojuly/are-node-js-modules-singletons-764ae97519af
+ */
+
+/**
+ * ORIGINAL SOURCE: src/app/g3w-ol/constants.js@3.8.6
+ */
+export const VM = new Vue();
+
+/**
+ * ORIGINAL SOURCE: src\app\gui\catalog\vue\catalogeventhub.js@3.8.6
+ */
+export const CatalogEventBus = new Vue();
+
+/**
+ * ORIGINAL SOURCE: src/app/gui/relations/vue/relationeventbus.js@3.8.6
+ */
+export const RelationEventBus = new Vue();
+
+/**
+ * ORIGINAL SOURCE: src/app/gui/sidebar/eventbus.js@3.8.6
+ */
+export const SidebarEventBus = new Vue();
+
+export default {
+  VM,
+  CatalogEventBus,
+  RelationEventBus,
+  SidebarEventBus,
+};
diff --git a/src/app/g3w-ol/constants.js b/src/app/g3w-ol/constants.js
deleted file mode 100644
index 024a5195c..000000000
--- a/src/app/g3w-ol/constants.js
+++ /dev/null
@@ -1,11 +0,0 @@
-//SPATIAL METHODS USED TO FIND FEATURES
-export const SPATIALMETHODS = ['intersects', 'within'];
-
-/**
- * MAIN VUE INSTANCE USED TO WATCH OBJECT CHANGES OR TO EMIT EVENTS
- * 
- * NB: node.js modules are singletons by default.
- * 
- * @see https://medium.com/@lazlojuly/are-node-js-modules-singletons-764ae97519af
- */
-export const VM = new Vue();
diff --git a/src/app/g3w-ol/controls/basequerypolygoncontrol.js b/src/app/g3w-ol/controls/basequerypolygoncontrol.js
index 9b1e80a42..d5bbf23df 100644
--- a/src/app/g3w-ol/controls/basequerypolygoncontrol.js
+++ b/src/app/g3w-ol/controls/basequerypolygoncontrol.js
@@ -2,7 +2,7 @@
  * @file
  * @since v3.8
  */
-import { SPATIALMETHODS } from 'g3w-ol/constants';
+import { SPATIAL_METHODS } from 'app/constant';
 
 const InteractionControl = require('g3w-ol/controls/interactioncontrol');
 const { merge }          = require('core/utils/ol');
@@ -13,7 +13,7 @@ const VALIDGEOMETRIES    = Geometry.getAllPolygonGeometryTypes();
 const BaseQueryPolygonControl = function(options = {}) {
 
   const {
-    spatialMethod=SPATIALMETHODS[0],
+    spatialMethod=SPATIAL_METHODS[0],
     onSelectlayer,
     interactionClass
   } = options;
diff --git a/src/app/g3w-ol/controls/interactioncontrol.js b/src/app/g3w-ol/controls/interactioncontrol.js
index fa531967f..114fb2006 100644
--- a/src/app/g3w-ol/controls/interactioncontrol.js
+++ b/src/app/g3w-ol/controls/interactioncontrol.js
@@ -1,4 +1,5 @@
-import { VM, SPATIALMETHODS } from 'g3w-ol/constants';
+import { SPATIAL_METHODS } from 'app/constant';
+import { VM } from 'app/eventbus';
 import GUI from 'services/gui';
 import ControlsRegistry from 'store/map-controls'
 
@@ -240,7 +241,7 @@ proto.createControlTool = function(toggledTool={}) {
       const method = this.getSpatialMethod();
       this.toggledTool = {
         data() {
-          this.methods = SPATIALMETHODS;
+          this.methods = SPATIAL_METHODS;
           return {
             method
           }
diff --git a/src/app/g3w-ol/controls/querybboxcontrol.js b/src/app/g3w-ol/controls/querybboxcontrol.js
index 33d1fe16d..223492c5f 100644
--- a/src/app/g3w-ol/controls/querybboxcontrol.js
+++ b/src/app/g3w-ol/controls/querybboxcontrol.js
@@ -1,4 +1,4 @@
-import { SPATIALMETHODS } from 'g3w-ol/constants';
+import { SPATIAL_LMETHODS } from 'app/constant';
 import GUI from 'services/gui';
 import DataRouterService from 'services/data';
 import ProjectsRegistry from 'store/projects';
@@ -24,7 +24,7 @@ const condition = {
 const QueryBBoxControl = function(options = {}) {
 
   const {
-    spatialMethod = SPATIALMETHODS[0]
+    spatialMethod = SPATIAL_METHODS[0]
   } = options;
 
   /**
diff --git a/src/app/g3w-ol/projection/projections.js b/src/app/g3w-ol/projection/projections.js
index 58a9bad5f..64e4398af 100644
--- a/src/app/g3w-ol/projection/projections.js
+++ b/src/app/g3w-ol/projection/projections.js
@@ -1,6 +1,6 @@
 import { API_BASE_URLS } from 'constant';
 
-const Projection       = require('./projection');
+const Projection       = require('g3w-ol/projection/projection');
 const { XHR }          = require('core/utils/utils');
 const {normalizeEpsg } = require('core/utils/geo');
 
diff --git a/src/app/gui/catalog/vue/catalogeventhub.js b/src/app/gui/catalog/vue/catalogeventhub.js
deleted file mode 100644
index 5571295be..000000000
--- a/src/app/gui/catalog/vue/catalogeventhub.js
+++ /dev/null
@@ -1,8 +0,0 @@
-/**
- * NB: node.js modules are singletons by default.
- * 
- * @see https://medium.com/@lazlojuly/are-node-js-modules-singletons-764ae97519af
- */
-const CatalogEventHub = new Vue();
-
-export default CatalogEventHub;
diff --git a/src/app/gui/relations/vue/relationeventbus.js b/src/app/gui/relations/vue/relationeventbus.js
deleted file mode 100644
index a03a77035..000000000
--- a/src/app/gui/relations/vue/relationeventbus.js
+++ /dev/null
@@ -1,6 +0,0 @@
-/**
- * NB: node.js modules are singletons by default.
- * 
- * @see https://medium.com/@lazlojuly/are-node-js-modules-singletons-764ae97519af
- */
-module.exports = new Vue();
\ No newline at end of file
diff --git a/src/app/gui/sidebar/eventbus.js b/src/app/gui/sidebar/eventbus.js
deleted file mode 100644
index d2ef851a3..000000000
--- a/src/app/gui/sidebar/eventbus.js
+++ /dev/null
@@ -1,6 +0,0 @@
-/**
- * NB: node.js modules are singletons by default.
- * 
- * @see https://medium.com/@lazlojuly/are-node-js-modules-singletons-764ae97519af
- */
-export default new Vue();
\ No newline at end of file
diff --git a/src/components/Catalog.vue b/src/components/Catalog.vue
index ba907e0ab..1924690d8 100644
--- a/src/components/Catalog.vue
+++ b/src/components/Catalog.vue
@@ -123,7 +123,7 @@
 
 <script>
 import { MAP_SETTINGS } from 'app/constant';
-import CatalogEventHub from 'gui/catalog/vue/catalogeventhub';
+import { CatalogEventBus as VM } from 'app/eventbus';
 import ChangeMapThemesComponent from 'components/CatalogChangeMapThemes.vue';
 import CatalogLayerContextMenu from 'components/CatalogLayerContextMenu.vue';
 import CatalogLayersStoresRegistry from 'store/catalog-layers';
@@ -210,10 +210,10 @@ export default {
         }
       });
       if ('tab' === this.legend.place) {
-        CatalogEventHub.$emit('layer-change-style');
+        VM.$emit('layer-change-style');
       } else {
         // get all layer tha changes style
-        changeStyleLayersId.forEach(layerId => { CatalogEventHub.$emit('layer-change-style', { layerId }); });
+        changeStyleLayersId.forEach(layerId => { VM.$emit('layer-change-style', { layerId }); });
       }
     },
 
@@ -289,7 +289,7 @@ export default {
     /**
      * @TODO add description
      */
-    CatalogEventHub.$on('unselectionlayer', (storeid, layerstree) => {
+     VM.$on('unselectionlayer', (storeid, layerstree) => {
       if (layerstree.external) {
         GUI.getService('queryresults').clearSelectionExtenalLayer(layerstree);
       } else {
@@ -300,21 +300,21 @@ export default {
     /**
      * @TODO add description
      */
-    CatalogEventHub.$on('activefiltertokenlayer', async (storeid, layerstree) => {
+     VM.$on('activefiltertokenlayer', async (storeid, layerstree) => {
       layerstree.filter.active = await CatalogLayersStoresRegistry.getLayersStore(storeid).getLayerById(layerstree.id).toggleFilterToken();
     });
 
     /**
      * Handle visibilty change on legend item
      */
-    CatalogEventHub.$on('treenodevisible', layer => {
+     VM.$on('treenodevisible', layer => {
       GUI.getService('map').emit('cataloglayervisible', layer);
     });
 
     /**
      * Handle legend item select (single mouse click ?)
      */
-    CatalogEventHub.$on('treenodeselected', function (storeid, node) {
+     VM.$on('treenodeselected', function (storeid, node) {
       let layer = CatalogLayersStoresRegistry.getLayersStore(storeid).getLayerById(node.id);
       // emit signal of select layer from catalog
       if (!layer.isSelected()) {
@@ -330,7 +330,7 @@ export default {
     /**
      * Handle temporary external layer add
      */
-    CatalogEventHub.$on('treenodeexternalselected', layer => {
+    VM.$on('treenodeexternalselected', layer => {
       GUI
         .getService('catalog')
         .setSelectedExternalLayer({ layer, type: 'vector', selected: !layer.selected})
diff --git a/src/components/CatalogLayerContextMenu.vue b/src/components/CatalogLayerContextMenu.vue
index a3ca1a37c..fb84163f6 100644
--- a/src/components/CatalogLayerContextMenu.vue
+++ b/src/components/CatalogLayerContextMenu.vue
@@ -219,7 +219,7 @@
 
   import LayerOpacityPicker from "components/LayerOpacityPicker.vue";
 
-  import CatalogEventHub from 'gui/catalog/vue/catalogeventhub';
+  import { CatalogEventBus as VM } from 'app/eventbus';
   import CatalogLayersStoresRegistry from 'store/catalog-layers';
   import ApplicationService from 'services/application';
   import GUI from 'services/gui';
@@ -667,7 +667,7 @@
           const layerId = this.layerMenu.layer.id;
           const layer = CatalogLayersStoresRegistry.getLayerById(this.layerMenu.layer.id);
           if (layer) {
-            CatalogEventHub.$emit('layer-change-style', {
+            VM.$emit('layer-change-style', {
               layerId,
               style: this.layerMenu.stylesMenu.style
             });
@@ -778,7 +778,7 @@
     },
 
     created() {
-      CatalogEventHub.$on('showmenulayer', async (layerstree, evt) => {
+      VM.$on('showmenulayer', async (layerstree, evt) => {
         this._hideMenu();
         await this.$nextTick();
         this.layerMenu.left = evt.x;
diff --git a/src/components/CatalogLayerLegend.vue b/src/components/CatalogLayerLegend.vue
index 8d4261328..4471d21c4 100644
--- a/src/components/CatalogLayerLegend.vue
+++ b/src/components/CatalogLayerLegend.vue
@@ -66,7 +66,7 @@
 
 <script>
   import GUI from 'services/gui';
-  import CatalogEventHub from 'gui/catalog/vue/catalogeventhub';
+  import { CatalogEventBus as VM } from 'app/eventbus';
   import CatalogLayersStoresRegistry from 'store/catalog-layers';
   import ProjectsRegistry from 'store/projects';
   import ClickMixin from 'mixins/click';
@@ -381,7 +381,7 @@
       this.mapReady = false;
 
       // listen layer change style event
-      CatalogEventHub.$on('layer-change-style', this.onChangeLayerLegendStyle);
+      VM.$on('layer-change-style', this.onChangeLayerLegendStyle);
 
       // Get all legend graphics of a layer when start
       // need to exclude wms source
@@ -392,7 +392,7 @@
     },
 
     beforeDestroy() {
-      CatalogEventHub.$off('layer-change-style', this.onChangeLayerLegendStyle);
+      VM.$off('layer-change-style', this.onChangeLayerLegendStyle);
     },
 
   }
diff --git a/src/components/CatalogLayersLegendItems.vue b/src/components/CatalogLayersLegendItems.vue
index 6df8ce827..3aa807e13 100644
--- a/src/components/CatalogLayersLegendItems.vue
+++ b/src/components/CatalogLayersLegendItems.vue
@@ -26,7 +26,7 @@
 </template>
 
 <script>
-import CatalogEventHub from 'gui/catalog/vue/catalogeventhub';
+import { CatalogEventBus as VM } from 'app/eventbus';
 import CatalogLayersStoresRegistry from 'store/catalog-layers';
 import ApplicationService from 'services/application';
 import ProjectsRegistry from 'store/projects';
@@ -285,7 +285,7 @@ export default {
     /**
      * listen when layer has changed style
      */
-    CatalogEventHub.$on('layer-change-style', (options={}) => {
+    VM.$on('layer-change-style', (options={}) => {
       this.getLegendSrc();
     });
   },
diff --git a/src/components/CatalogTristateTree.vue b/src/components/CatalogTristateTree.vue
index d96421705..fdc17a946 100644
--- a/src/components/CatalogTristateTree.vue
+++ b/src/components/CatalogTristateTree.vue
@@ -191,7 +191,7 @@
 
 <script>
 import LayerLegend from 'components/CatalogLayerLegend.vue';
-import CatalogEventHub from 'gui/catalog/vue/catalogeventhub';
+import { CatalogEventBus as VM } from 'app/eventbus';
 import CatalogLayersStoresRegistry from 'store/catalog-layers';
 import ClickMixin from 'mixins/click';
 import GUI from 'services/gui';
@@ -437,7 +437,7 @@ export default {
            * @TODO is it necessary to emit the `layer-change-style` event here?
            */
           // if (visible && 'toc' === this.legendplace) {
-          //  setTimeout(() => CatalogEventHub.$emit('layer-change-style', { layerId: id }));
+          //  setTimeout(() => VM.$emit('layer-change-style', { layerId: id }));
           // }
           if (parentGroup.mutually_exclusive) {
             parentGroup.nodes.forEach(node => node.checked = node.id === id);
@@ -449,17 +449,17 @@ export default {
         } else {
           layer.setVisible(false);
         }
-        CatalogEventHub.$emit('treenodevisible', layer);
+        VM.$emit('treenodevisible', layer);
       }
 
     },
 
     toggleFilterLayer() {
-      CatalogEventHub.$emit('activefiltertokenlayer', this.storeid, this.layerstree);
+      VM.$emit('activefiltertokenlayer', this.storeid, this.layerstree);
     },
 
     clearSelection() {
-      CatalogEventHub.$emit('unselectionlayer', this.storeid, this.layerstree);
+      VM.$emit('unselectionlayer', this.storeid, this.layerstree);
     },
 
     toggle() {
@@ -473,8 +473,8 @@ export default {
     /**
      * Select legend item
      *
-     * @fires CatalogEventHub~treenodeexternalselected
-     * @fires CatalogEventHub~treenodeselected
+     * @fires CatalogEventBus~treenodeexternalselected
+     * @fires CatalogEventBus~treenodeselected
      */
     select() {
       // skip when `selected === undefined` (unselectable layer, eg. an external WMS layer) 
@@ -482,9 +482,9 @@ export default {
         return;
       }
       if (this.layerstree.external) {
-        CatalogEventHub.$emit('treenodeexternalselected', this.layerstree);
+        VM.$emit('treenodeexternalselected', this.layerstree);
       } else if (!this.isGroup && !this.isTable) {
-        CatalogEventHub.$emit('treenodeselected', this.storeid, this.layerstree);
+        VM.$emit('treenodeselected', this.storeid, this.layerstree);
       }
     },
 
@@ -547,7 +547,7 @@ export default {
         !this.isGroup &&
         (this.layerstree.openattributetable || this.layerstree.downloadable || this.layerstree.geolayer || this.layerstree.external)
       ) {
-        CatalogEventHub.$emit('showmenulayer', layerstree, evt);
+        VM.$emit('showmenulayer', layerstree, evt);
       }
     }
 
diff --git a/src/components/LayerOpacityPicker.vue b/src/components/LayerOpacityPicker.vue
index 44fc29459..929b1e393 100644
--- a/src/components/LayerOpacityPicker.vue
+++ b/src/components/LayerOpacityPicker.vue
@@ -45,7 +45,7 @@
 
 <script>
   import CatalogLayersStoresRegistry from 'store/catalog-layers';
-  import CatalogEventHub from 'gui/catalog/vue/catalogeventhub';
+  import { CatalogEventBus as VM } from 'app/eventbus';
 
   export default {
 
@@ -77,7 +77,7 @@
       /**
        * @param {{ id:? string, value: number }}
        * 
-       * @fires CatalogEventHub~layer-change-opacity
+       * @fires CatalogEventBus~layer-change-opacity
        */
       setLayerOpacity( { id = this.layer.id, value: opacity }) {
         // skip if nothing has changed
@@ -87,7 +87,7 @@
         this.layer.opacity = opacity;
         const layer = CatalogLayersStoresRegistry.getLayerById(id);
         if (layer) {
-          CatalogEventHub.$emit('layer-change-opacity', { layerId: id });
+          VM.$emit('layer-change-opacity', { layerId: id });
           layer.change();
         }
       },
diff --git a/src/components/Relation.vue b/src/components/Relation.vue
index 0abad7d5e..183d020e3 100644
--- a/src/components/Relation.vue
+++ b/src/components/Relation.vue
@@ -70,9 +70,9 @@ import DownloadFormats from 'components/QueryResultsActionDownloadFormats.vue';
 import CatalogLayersStoresRegistry from 'store/catalog-layers';
 import GUI from 'services/gui';
 import { fieldsMixin, resizeMixin } from 'mixins';
+import { RelationEventBus as VM } from 'app/eventbus';
 
 const { throttle } = require('core/utils/utils');
-const RelationPageEventBus = require('gui/relations/vue/relationeventbus');
 
 let SIDEBARWIDTH;
 
@@ -146,7 +146,7 @@ export default {
           } : () => this.saveRelation(layer.getDownloadUrl(downloadformats[0]))
         }
       }
-      RelationPageEventBus.$on('reload', () => {
+      VM.$on('reload', () => {
         this.reloadLayout();
       });
       this.showChart = throttle(async ()=> {
diff --git a/src/components/RelationsPage.vue b/src/components/RelationsPage.vue
index f2a5427a2..fc9749f7b 100644
--- a/src/components/RelationsPage.vue
+++ b/src/components/RelationsPage.vue
@@ -23,9 +23,9 @@ import GUI from 'services/gui';
 import RelationsComponent from 'components/Relations.vue';
 import RelationComponent from 'components/Relation.vue';
 import {G3W_FID, LIST_OF_RELATIONS_TITLE} from 'constant';
+import { RelationEventBus as VM } from 'app/eventbus';
 
 const {getFeaturesFromResponseVectorApi} = require('core/utils/geo');
-const RelationPageEventBus = require('gui/relations/vue/relationeventbus');
 
 export default {
 
@@ -71,7 +71,7 @@ export default {
       this.$options.service.saveRelations(type)
     },
     reloadLayout() {
-      RelationPageEventBus.$emit('reload');
+      VM.$emit('reload');
     },
     showChart(container, relationData){
       const relationLayerId = this.relation.referencingLayer;
diff --git a/src/components/Sidebar.vue b/src/components/Sidebar.vue
index ba30cded1..df4f326ee 100644
--- a/src/components/Sidebar.vue
+++ b/src/components/Sidebar.vue
@@ -40,7 +40,7 @@
 
 <script>
   import ApplicationState from 'store/application-state';
-  import SIDEBAREVENTBUS from 'gui/sidebar/eventbus';
+  import { SidebarEventBus as VM } from 'app/eventbus';
   import sidebarService from 'services/sidebar';
 
   const { t } = require('core/i18n/i18n.service');
@@ -91,7 +91,7 @@
     },
     created() {
       this.iframe = ApplicationState.iframe;
-      SIDEBAREVENTBUS.$on('sidebaritemclick', ()=> $('.sidebar-toggle').click())
+      VM.$on('sidebaritemclick', ()=> $('.sidebar-toggle').click())
     }
   }
 </script>
diff --git a/src/components/SidebarItem.vue b/src/components/SidebarItem.vue
index ea2212d9f..a0b337915 100644
--- a/src/components/SidebarItem.vue
+++ b/src/components/SidebarItem.vue
@@ -22,7 +22,7 @@
 </template>
 
 <script>
-  import SIDEBAREVENTBUS from 'gui/sidebar/eventbus';
+  import { SidebarEventBus as VM } from 'app/eventbus';
   import SidebarItemAction from 'components/SidebarItemAction.vue';
 
   export default {
@@ -62,7 +62,7 @@
               }
             }
           });
-          !this.component.collapsible && isMobile.any && SIDEBAREVENTBUS.$emit('sidebaritemclick');
+          !this.component.collapsible && isMobile.any && VM.$emit('sidebaritemclick');
         }
         this.component.setOpen(!this.component.state.open);
       }
diff --git a/src/store/map-controls.js b/src/store/map-controls.js
index eded9de07..d3c15c942 100644
--- a/src/store/map-controls.js
+++ b/src/store/map-controls.js
@@ -5,7 +5,7 @@
 
 import ApplicationService from 'services/application';
 import GUI from 'services/gui';
-import { VM } from 'g3w-ol/constants';
+import { VM } from 'app/eventbus';
 
 const { base, inherit } = require('core/utils/utils');
 const G3WObject = require('core/g3wobject');