src/vs/editor/contrib/zoneWidget/zoneWidget.ts/ZoneWidget/_decoratingElementsHeight
class ZoneWidget:	private _decoratingElementsHeight(): number {
		let lineHeight = this.editor.getOption(EditorOption.lineHeight);
		let result = 0;

		if (this.options.showArrow) {
			let arrowHeight = Math.round(lineHeight / 3);
			result += 2 * arrowHeight;
		}

		if (this.options.showFrame) {
			let frameThickness = Math.round(lineHeight / 9);
			result += 2 * frameThickness;
		}

		return result;
	}