[GREENFOOT-625] Auto-complete causes showing wrong compile errors

When using auto-complete (with Strg + space) I get errors. E.g. I write

{{this.abc = abc}}

The first abc is marked as error, the message is: cannot find symbol - variable ab

Two examples can be found here: https://www.youtube.com/watch?v=jmh06-pNMMs&t=11m40s https://www.youtube.com/watch?v=jmh06-pNMMs&t=18m6s

---

Issue metadata

• Issue type: Bug
• Priority: Medium
• Fix versions: 3.5.0