In recent weeks there are more issues with the WebKitGTK HTML renderer widget used by Liferea. Here is some insight on these problems and if you are impacted how to workaround…
1. Broken/missing CSS
When you upgrade your install WebkitGTK library to version 2.32 or newer CSS decorations in Liferea will vanish. This is due to new and more strict security settings of Webkit.
CSS styles are properly applied again starting with Liferea 1.13.5.
Impact: Happens to all users once upgrading to WebKitGTK 2.23+
Workaround: Upgrade to Liferea 1.13.5 or downgrade WebKitGTK
2. Crashes/flickering upon video playback
It seems that the Webkit rendering process dies if the gstreamer library crashes in background. When this happens you see the HTML widget go blank or sometimes do flicker for 2-3 seconds before going blank. In all those case a video playback was started, which often is an video auto-play of the visited website and causes a crash in gstreamer.
Impact: Affects not all users, quite rare
Workaround: Disable Javascript in the preference to prevent automatic video playback.