Unfocused window causes timeout causes error

[nickyout]

When loadFonts is called and the window is not focused (Chrome 43), the timeout occurs. This results in the _testContainer to be detached from the DOM. Once the window regains focus, the SizeWatcher throws the Error Can't set scroll position of scroll watchers. SizeWatcher is not in the DOM tree..

Passing null for timeout will resolve this issue, but it took a while before I realised what was going on and I suspect there is a reason for the timeout feature to be enabled by default. I would like to suggest somehow detecting whether or not the window has focus, disabling the SizeWatcher, or maybe including this case in a FAQ on the bottom of the README. Or telling me what I was/am doing wrong.