The new notification badge acts funny on Opera 12. Symptoms include:
- The badge flashes on and off during the loading of the page, and when hovered
- Occasionally tabs have high CPU usage, even on background tabs (doing nothing)
- During loading of the page, area in top-right corner of the page is sometimes clickable, leading to Special:Notifications
For whatever reason, all this seems to be caused by using an SVG image in content property in CSS.