It uses a serif font, probably Times
I can replicate this, including a serif font in the search-box. I have tested Open Sans font and currently not running a local instance of the Open Sans font.
We have now reproduced this in certain situations. It seems to depend on the OS version and the fonts installed. We are investigating. Thanks!
With the latest release (1.1.5) fonts are now correctly showing sans-serif. See: http://goo.gl/a5Ygij
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