Fix interface for ifc viewer service

frontend/src/app/modules/bim/ifc_models/ifc-viewer/ifc-viewer.component.ts

@@ -59,7 +59,7 @@ export class IFCViewerComponent implements OnInit, OnDestroy {
         explorerElement: jQuery(".ifc-model-viewer--tree-panel")[0], // Left panel
         toolbarElement: element.find(".ifc-model-viewer--toolbar-container")[0], // Toolbar
         navCubeCanvasElement: element.find(".ifc-model-viewer--nav-cube-canvas")[0],
-        busyModelBackdropElement: document.querySelector(".xeokit-busy-modal-backdrop")
+        busyModelBackdropElement: element.find(".xeokit-busy-modal-backdrop")[0]
       },
       this.Gon.get('ifc_models', 'projects') as any[]
     );

frontend/src/app/modules/bim/ifc_models/ifc-viewer/ifc-viewer.service.ts

@@ -7,7 +7,7 @@ export interface XeokitElements {
   explorerElement:HTMLElement;
   toolbarElement:HTMLElement;
   navCubeCanvasElement:HTMLElement;
-  sectionPlanesOverviewCanvasElement:HTMLElement;
+  busyModelBackdropElement:HTMLElement;
 }
 
 export interface BCFCreationOptions {