src/vs/workbench/browser/parts/editor/editorDropTarget.ts/DropOverlay/create
class DropOverlay:	private create(): void {
		const overlayOffsetHeight = this.getOverlayOffsetHeight();

		// Container
		const container = this.container = document.createElement('div');
		container.id = DropOverlay.OVERLAY_ID;
		container.style.top = `${overlayOffsetHeight}px`;

		// Parent
		this.groupView.element.appendChild(container);
		this.groupView.element.classList.add('dragged-over');
		this._register(toDisposable(() => {
			this.groupView.element.removeChild(container);
			this.groupView.element.classList.remove('dragged-over');
		}));

		// Overlay
		this.overlay = document.createElement('div');
		this.overlay.classList.add('editor-group-overlay-indicator');
		container.appendChild(this.overlay);

		// Overlay Event Handling
		this.registerListeners(container);

		// Styles
		this.updateStyles();
	}