The OOM bug due to stacked textblocks / richtextboxes hit hard and I had to find an alternative. Currently using the WebBrowser control. It's faster anyways, but it's not a real Silverlight control so it's tough to use bindings. Will try to see if the highlighter can be made to work.

One of the consequences is that the article view can't be transparent (boo!). So, I'll need to find a trick to fake it or find something else to make it look good. I'm not sure the former is entirely possible for all resolutions...