The team is fixing this for the next release but for now the upgrades don't add correct file type for the editor's template features to fully work.
Go to: Host Settings -> Advanced Settings -> Allowable File Extensions and ensure 'htmtemplate' is included.
I have: template,docx,xlsx,pptx,swf,js,jpg,jpeg,jpe,gif,bmp,png,doc,xls,ppt,pdf,txt,xml,xsl,css,zip,htmtemplate
Templates allow users to create their own complex snippets. Great for things like signatures.