I removed YahooWeather plugin, even the yweather.xml-file in tmp-directory, restarted and still the 5-day weather pic is remaining in the second info bar. The plugin-button vanished in the plugin menu.
I made the a new settings backup, deleted the old ones, downloaded the image, reflashed, restored the settings, no YahooWeather visible. Then I also restored the plugins - and the Yahooweather was there again installed!
Where is it hiding for reinstalling? How to get rid of it completely?