isUsedInTractor(track) {
		const tractor = track.parentElement.parentElement;
		const trackIndex = this.getTrackIndex(track);

		const filters = tractor.getElementsByTagName('filter');
		for (let filter of filters) {
			if (filter.getAttribute('track') === trackIndex.toString()) return true;
		}

		const transitions = tractor.getElementsByTagName('transition');
		for (let transition of transitions) {
			if (transition.getAttribute('a_track') === trackIndex.toString()) return true;
			if (transition.getAttribute('b_track') === trackIndex.toString()) return true;
		}

		return false;
	}
Check if track is used in any filter or transition

@param {Element} track
@return {boolean}