src/vs/workbench/browser/parts/editor/editorDropTarget.ts/EditorDropTarget/registerListeners
class EditorDropTarget:	private registerListeners(): void {
		this._register(addDisposableListener(this.container, EventType.DRAG_ENTER, e => this.onDragEnter(e)));
		this._register(addDisposableListener(this.container, EventType.DRAG_LEAVE, () => this.onDragLeave()));
		this._register(addDisposableListener(this.container, EventType.DRAG_OVER, e => {
			if (!this.overlay) {
				this.onDragEnter(e);
			}
		}));
		[this.container, window].forEach(node => this._register(addDisposableListener(node as HTMLElement, EventType.DRAG_END, () => this.onDragEnd())));
	}