addControlElement (element, key) {
		const t = this;

		if (t.featurePosition[key] !== undefined) {
			const child = t.getElement(t.controls).children[t.featurePosition[key] - 1];
			child.parentNode.insertBefore(element, child.nextSibling);
		} else {
			t.getElement(t.controls).appendChild(element);
			const children = t.getElement(t.controls).children;
			for (let i = 0, total = children.length; i < total; i++) {
				if (element === children[i]) {
					t.featurePosition[key] = i;
					break;
				}
			}
		}
	}
Add featured control element and cache its position in case features are reset

@param {HTMLElement} element
@param {String} key