explorerView: header area, also update on change workspace roots

src/vs/workbench/parts/files/browser/views/explorerView.ts

@@ -120,7 +120,12 @@ export class ExplorerView extends CollapsibleView {
 
 	public renderHeader(container: HTMLElement): void {
 		const titleDiv = $('div.title').appendTo(container);
-		$('span').text(this.contextService.getWorkspace().name).title(labels.getPathLabel(this.contextService.getWorkspace().resource.fsPath, void 0, this.environmentService)).appendTo(titleDiv);
+		const setHeader = () => {
+			const title = this.contextService.getWorkspace2().roots.map(root => labels.getPathLabel(root.fsPath, void 0, this.environmentService)).join();
+			$('span').text(this.contextService.getWorkspace2().name).title(title).appendTo(titleDiv);
+		};
+		this.toDispose.push(this.contextService.onDidChangeWorkspaceRoots(() => setHeader()));
+		setHeader();
 
 		super.renderHeader(container);
 	}