Why doesn't it associate with all wikipedia articles?

Steve -- this could happen for a couple of reasons.

1. We are a bit selective about terms to link, to avoid cluttering the page with too many links. We tend to drop terms that are relatively more common than others.
2. The topic has been added to Wikipedia recently, and we've not yet added it to our index.

Here's what you can do. Select/highlight the term, right-click and select "Mash <this>" from the menu. Alternatively, if you have a callout open, you can just click on the term and type in the term you are interested in.

Thanks for your inquiry. I hope you found my response useful.</this>