Migrate from TestComplete v14 to v15, ES5 to ES6

Dear TestComplete Users,

Am trying to move from v14 to v15 and start using ES6 instead of ES5. I have a question which may be obvious to you, but am unable to work around. Looking forward to suggestions.

I installed v15 and tried a sample script to confirm it supports ES6. It does!  See picture below.

Next I opened a project that always worked well in v14. It worked in v15 too. But when I try to run the same code in the picture above in a new or existing script, it doesn't work. What am I missing?  Is there a project setting?

If you have other experiences moving to ES6, please do share.