src/vs/workbench/contrib/mergeEditor/browser/view/fixedZoneWidget.ts/FixedZoneWidget/constructor
class FixedZoneWidget:	constructor(
		private readonly editor: ICodeEditor,
		viewZoneAccessor: IViewZoneChangeAccessor,
		afterLineNumber: number,
		height: number,
		viewZoneIdsToCleanUp: string[],
	) {
		super();

		this.viewZoneId = viewZoneAccessor.addZone({
			domNode: document.createElement('div'),
			afterLineNumber: afterLineNumber,
			heightInPx: height,
			onComputedHeight: (height) => {
				this.widgetDomNode.style.height = `${height}px`;
			},
			onDomNodeTop: (top) => {
				this.widgetDomNode.style.top = `${top}px`;
			}
		});
		viewZoneIdsToCleanUp.push(this.viewZoneId);

		this.widgetDomNode.style.left = this.editor.getLayoutInfo().contentLeft + 'px';

		this.editor.addOverlayWidget(this.overlayWidget);

		this._register({
			dispose: () => {
				this.editor.removeOverlayWidget(this.overlayWidget);
			},
		});
	}