src/vs/workbench/browser/layout.ts/Layout/focusPart
class Layout:	focusPart(part: Parts): void {
		switch (part) {
			case Parts.EDITOR_PART:
				this.editorGroupService.activeGroup.focus();
				break;
			case Parts.PANEL_PART: {
				const activePanel = this.paneCompositeService.getActivePaneComposite(ViewContainerLocation.Panel);
				if (activePanel) {
					activePanel.focus();
				}
				break;
			}
			case Parts.SIDEBAR_PART: {
				const activeViewlet = this.paneCompositeService.getActivePaneComposite(ViewContainerLocation.Sidebar);
				if (activeViewlet) {
					activeViewlet.focus();
				}
				break;
			}
			case Parts.ACTIVITYBAR_PART:
				(this.getPart(Parts.ACTIVITYBAR_PART) as ActivitybarPart).focus();
				break;
			case Parts.STATUSBAR_PART:
				this.statusBarService.focus();
			default: {
				// Title Bar & Banner simply pass focus to container
				const container = this.getContainer(part);
				if (container) {
					container.focus();
				}
			}
		}
	}