UITableView Section Title Glitch?

Question

I have a view controller with a tableview inside that is grouped. This produces a very weird glitch that causes the sectionTitles to show at the side. I've attached top, trailing, bottom, and leading constraints to the superview for the tableview and I've tested returning UITableViewCell() in cellForRowAtIndexPath to see if it was the cell that was causing the problem, but it still shows it like this.

var sectionTitles = ["Customer Orders", "Unprocessed Orders", "Processed Orders"]


func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    return sectionTitles.count
}

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return 1
}

func sectionIndexTitlesForTableView(tableView: UITableView) -> [String]? {
    return sectionTitles
}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell{
    let cell = tableView.dequeueReusableCellWithIdentifier(CONSTANTS.CELL_IDENTIFIERS.ORDER_CELL) as! OrderTableViewCell
    return cell
}

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    // Perform segue to order list in future
}

func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
    return 117.0
}

Answer 1

After hours I figured out that I didn't implement this method

override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
    return sectionTitles[section]
}