I've been running into a rather strange problem in Neatline, running Neatline 2.5.0 and Omeka 2.3.1. Whenever Google Streets or Google Physical is used as the default spatial layer, the tiles don't show up. Any points or polygons are displayed against a white background, and I don't even see any errors in the Chrome console.
What's odd is that if another layer is the default, and either the Google Hybrid or Google Satellite layers are present, Google Streets and Google Physical display just fine when selected. The problem layers still won't show up if they're the default, but if another layer is selected and then a problem layer is selected, they work fine.
The instances of Omeka that I'm running are being used for classes that are still in session, so I've spun up a new instance on the same server to demonstrate the issue here: http://dighist.fas.harvard.edu/omeka_forums/neatline_error/neatline. There are three neatline exhibits, one where Google Streets is included and doesn't work at all (streets nodisplay), one where streets works fine when selected (streets working), and one where streets doesn't display initally, but will display when re-selected (streets default).
This topic here (http://omeka.org/forums/topic/neatline-newbie-google-maps-dont-display) sounds similar to what I'm experiencing, but didn't go anywhere. If anyone's run into this before, especially if you've fixed it, I'd love to hear about it.