         var ret: Letter?
         if self.title != ""
         {
-            var idChar = self.title[self.title.startIndex]
+            let idChar = self.title[self.title.startIndex]
             if idChar != "$"
             {
                 ret = Letter(rawValue: idChar)

            timerMouseUp = true

            singleStep.fixUpIdentifier()
            self.buttonPressed(singleStep)

        }
    }

        }
    }


    /// Fix the identifier for the button
    func fixUpIdentifier()
    {
        let rawCharacters = textField.stringValue
        let charactersLeft = rawCharacters.uppercased()
        var nextLetter: Letter?
        var chosenIndex: String.Index?

		for (index, character) in charactersLeft.enumerated()
        {
            if let candidateLetter = Letter(rawValue: character),
                candidateLetter != .UpperBound // Could be if they typed a $
            {
                nextLetter = candidateLetter
                chosenIndex = charactersLeft.index(charactersLeft.startIndex, offsetBy: index)
				break
            }
        }

        var  replacementString = ""
        if let nextLetter = nextLetter, let chosenIndex = chosenIndex
        {
            self._letter = nextLetter
            replacementString = String(rawCharacters.suffix(from: chosenIndex))
        }
        else
        {
