I was wondering if you could add this function to your _browsermanagement.py file? This will enable the selenium tests to pull information straight from the developer console. This feature will give a better picture of what is going on with the back end when running these kind of tests within a frame buffer like XVFB.

def printMyLogs(self):
sampleLogsArray = []
for entry in self._current_browser().get_log('browser'):
print entry
sampleLogsArray.append(entry)

    return sampleLogsArray