Also using v2.30.0.1-0ubuntu3. Changing the "Application Font" setting works for me, but I don't agree that this is the correct design. First, it is quite common to provide application-specific font overrides (e.g., Firefox, Chrome, gedit, GNOME Terminal). Second, it is perfectly understandable to desire different font settings for small snippets of text appearing in menu titles vs. larger blocks of text as appear in Gwibber status updates. At the very least, the appropriate system-wide setting to pick up for status updates is the "Document Font" rather than the "Application Font". This is the setting that Empathy uses for chat sessions (it uses the "Application Font" for the contact list).
Also using v2.30.0.1-0ubuntu3. Changing the "Application Font" setting works for me, but I don't agree that this is the correct design. First, it is quite common to provide application- specific font overrides (e.g., Firefox, Chrome, gedit, GNOME Terminal). Second, it is perfectly understandable to desire different font settings for small snippets of text appearing in menu titles vs. larger blocks of text as appear in Gwibber status updates. At the very least, the appropriate system-wide setting to pick up for status updates is the "Document Font" rather than the "Application Font". This is the setting that Empathy uses for chat sessions (it uses the "Application Font" for the contact list).