I found following information in our call database.
This behavior is because the Sharepoint 2010 master page causes all pages to be loaded in IE8 document mode, which doesn't support HTML5. And PI Coresight 2014 uses HTML5.
You should see something like this in your Advanced Editor:
As a temporary solution you can change this through IE Dev Tools (click F12 and set Document mode to Edge) just to see if it works. But every time the page is reloaded it will go back to IE8 mode because of Sharepoint.
As a permanent solution you would have to change your master page itself, but this should be taken by your SharePoint administrator. If you upgrade to SharePoint 2013, this issue would not represent.
Additional information about this can be found on the MSDN blog here:http://blogs.msdn.com/b/opal/archive/2010/09/16/ie9-sharepoint-2010-html5.aspx
That makes sense now. I'll start the conversation about a master page change with our SharePoint admins:)