There seems to be at least 5 different !DOCTYPE declarations used in Matterhorn html documents. In at least one (/engage/ui/index.html) this is causing problems when viewing it with Internet Explorer 8 on Windows 7 (x64).
Steps to reproduce:
1. Start Matterhorn and go to Matterhorn "Media Module" page with IE8
2. Click on the Matterhorn image in upper left corner to go back to main page. Nothing happens. Clicking on text "Media Module" works OK.
3. If you repeat the same on "Admin Tools" page, everything works OK.
Clicking on image or text (title) in the upper left corner should return you to the main page.
Workaround (if any):
Replace line with !DOCTYPE declaration in /modules/matterhorn-engage-ui/src/main/resources/ui/index.html to be the same as in /modules/matterhorn-admin-ui/src/main/resources/ui/*.html
This should probably be done elsewhere, too.