Warning with firefox using grid

Hello,

I'm testing evaluation grid before buy it.
I made a grid with only four rows and twenty columns but I have a lot of warnings in Firefox with this message "reference to undefined property this[this._controller[i][name]" in the file "aw.js' line 30. The move of the horizontal scroll bar is very slow. And Firefox is always like it's still connected to something, it permanently "runs".
What is the problem?
Thanks.

Which version of Firefox and which version of AW are you using? Do you see the same problem with standard examples or with your own code? Can you post an example to reproduce this?