Colin Eberhardt has updated his previous solution for automatically adding tooltips when a TextBlock Text is trimmed and now it supports both WPF and Silverlight.
Source: ScottLogic
I found a decent looking WPF solutions on the web and linked it in my article, however, based on the comments to my previous blog post, it looks like the WPF solution didn’t work too well, failing to respect font size etc… In this blog post I have updated my solution to be cross-platform, working on WPF and Silverlight.