Added correction that taxonomy picker crashed when SharePoint return default empty Guid on anchorId

Author: Victor POLLET

src/common/Constants.ts

@@ -108,4 +108,6 @@ export const InvariantCulture: ICultureInfo = {
         MonthGenitiveNames: ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December', ''],
         eras: [1, 'A.D.', null, 0]
     }
-};
+};
+
+export const EmptyGuid: string = "00000000-0000-0000-0000-000000000000";

src/controls/taxonomyPicker/TermPicker.tsx

@@ -9,6 +9,7 @@ import * as strings from 'ControlStrings';
 import { Icon } from 'office-ui-fabric-react/lib/Icon';
 import { ExtensionContext } from '@microsoft/sp-extension-base';
 import { ITermSet } from "../../services/ISPTermStorePickerService";
+import { EmptyGuid } from '../../Common';
 
 export class TermBasePicker extends BasePicker<IPickerTerm, IBasePickerProps<IPickerTerm>>
 {
@@ -118,7 +119,7 @@ export default class TermPicker extends React.Component<ITermPickerProps, ITermP
       } = this.props;
 
       let terms: IPickerTerm[] = [];
-      if (termPickerHostProps.anchorId) {
+      if (termPickerHostProps.anchorId && termPickerHostProps.anchorId !== EmptyGuid) {
         terms = await this.termsService.searchTermsByTermId(filterText, termPickerHostProps.anchorId,);
       }
       else {