Environment: Device: Prestigio Grace x5 (Android 4.4.2); Build: Nightly 53.0a1 (2016-12-19); Prerequisites: Activity stream is enabled. Steps to reproduce: 1. Launch Firefox; 2. Access a webpage that has a long URL <e.g. https://crash-stats.mozilla.com/signature/?signature=java.lang.IllegalArgumentException%3A%20Sanitize%3AFinished%20was%20not%20registered%20at%20org.mozilla.gecko.EventDispatcher.unregisterListener(EventDispatcher.java)>; 3. Wait for about ~30 minutes so that the Highlights area updates with the accessed website (or bookmark that webpage so you don't have to wait). Expected result: Activity stream panel is properly updated and displayed. Actual result: Activity stream panel is displayed, but the favicon of the long URL from the Highlights area is displayed in the upper side of the frame, which gives the user an unpleasant visual experience. Notes: This is reproducible on both Phone and Tablet devices. The issue remains visible even with rotating the device to landscape mode, but not so evident as in portrait mode. Please see the screenshots attached.

We are going to implement a new AS UI refresh soon probably.