See attached screenshot. it might be an issue with the way translations are html encoded (should we allow html entities, or force to use native UTF-8 for all characters?), or it might be a bug (missing html decoding before output).
Attachment: Example of broken ui with swedish language
I'd prefer removing html entities from translations.
Adding an html_entity_decode() to Piwik_Translate should fix it but obviously has some runtime cost.
Hmmm... might have to rethink this if using < and >.
Maybe the right thing would be to have the graph classes html entity decode the text.
Also, there is an issue with search engine keywords, that maybe shows that there is an issue with encoding these characters.
What was the search engine used that lead to the buggy keyword entry? It is possible to specify a charset for keyword for each search engine, which might help. Read for more info: http://piwik.org/faq/general/#faq_39
In , fixes #974 Swedish characters don't show up properly in UI, graphs