Popup: blue focus flash on android 4.2

So I tested this with Browserstack on android 4.2 and it fixed the problem.  However, when I run "grunt test" there are a number of test cases failing.  @arschmitz suggested I do a pull request so he can take a look.  So don't merge if it's breaking tests! :)
```$( currElement ) !== this.window[ 0 ]``` is incorrect, because ```$( currElement )``` is a jQuery object, whereas ```this.window[ 0 ]``` is a Window object. Comparing them like this will result in a comparison that is always true.

The comparison we want is ```currElement !== this.window[ 0 ]```.