Any input of an expression with empty string (see the attachments) does invalid syntax highlighting.
pull request merged
Submitted a pull request for this.
The empty double quoted example was fixed sometime, but for empty single quoted strings the highlighting is still incorrect.
The new expression 'println("" + "hello")' must not highlight fine anywhere.
Isn't it OK? Both examples run fine. The first highlights OK for me but not the second.
The problem in the first place is that the code you entered is not correct.
How would you want it to be highlighted?