Crash in Dartium when assigning an int to the alpha property

Hello,
I have a bug that make Dartium crash (aw, snap) but unfortunately, I'm not able to reproduce it in a small sample.
This is weird because I have no error message and it works in javascript.

I discovered that if in my code I change:
myField.alpha = 0;
to
myField.alpha = 0.0;
Then it works correctly.
So I propose this small change that solve my problem.

Maybe you have an idea of what the root cause can be and how to fix the problem in a different way.

Thank you.