Test at: http://attensi.com/static/outracks/ietest/index.html
This works in chrome and firefox but not IE.
Project is super simple: https://dl.dropboxusercontent.com/u/1881490/IETest.zip
(I had to replace the opensans-light font in the data directory of the build with a font that is usable in ie)
The issue still seems to be linked to IE’s special (strict) handling of fonts. We’ll dig a little bit further and see what we can do.
The problem is triggered by the fact that BasicTheme references more fonts that cause problems with IE (problems that unfortunately don’t trigger the same type of error messages as the opensans-light font you replaced). I’ll be adding a few tickets internally regarding js font support but as the WebGL backend is currently considered experimental I can’t provide any estimate for when they’ll be fixed.
The easiest fix for your project right now would be to use a different Theme with fewer / other fonts.