Merge pull request jupyter#6477 from brichet/fix/closable_tab

Change the tab renderer to allow adding closable tab

Author: jtpio

packages/tree-extension/src/index.ts

@@ -27,7 +27,8 @@ import { ITranslator } from '@jupyterlab/translation';
 import {
  caretDownIcon,
  folderIcon,
- runningIcon
+ runningIcon,
+ TabBarSvg
 } from '@jupyterlab/ui-components';
 
 import { Menu, MenuBar, TabPanel } from '@lumino/widgets';
@@ -113,7 +114,11 @@ const browserWidget: JupyterFrontEndPlugin<void> = {
  toolbarRegistry: IToolbarWidgetRegistry,
  manager: IRunningSessionManagers | null
  ): void => {
- const tabPanel = new TabPanel({ tabPlacement: 'top', tabsMovable: true });
+ const tabPanel = new TabPanel({
+ tabPlacement: 'top',
+ tabsMovable: true,
+ renderer: TabBarSvg.defaultRenderer
+ });
  tabPanel.addClass('jp-TreePanel');
 
  const trans = translator.load('notebook');