src/vs/workbench/browser/parts/editor/editorPart.ts/EditorPart/createContentArea
class EditorPart:	override createContentArea(parent: HTMLElement, options?: IEditorPartCreationOptions): HTMLElement {

		// Container
		this.element = parent;
		this.container = document.createElement('div');
		this.container.classList.add('content');
		parent.appendChild(this.container);

		// Grid control
		this.doCreateGridControl(options);

		// Centered layout widget
		this.centeredLayoutWidget = this._register(new CenteredViewLayout(this.container, this.gridWidgetView, this.globalMemento[EditorPart.EDITOR_PART_CENTERED_VIEW_STORAGE_KEY]));

		// Drag & Drop support
		this.setupDragAndDropSupport(parent, this.container);

		// Signal ready
		this.whenReadyResolve?.();

		// Signal restored
		Promises.settled(this.groups.map(group => group.whenRestored)).finally(() => {
			this.whenRestoredResolve?.();
		});

		return this.container;
	}