User Mention feature of Instructional Text Macro does not work with various browsers

Instructional text in a global page template marked with user mention feature does not work with various browsers (Chrome 36, Firefox 31, IE 11 all on Windows 7. Works as a charm with Safari on OSX).

How to repeat:
1. Create a template
2. Create an instructional text like "Type @ to add a user mention"
3. Mark instructional text as "User mention"
4. Save template an create a new page using the template
5. Click on the instructional text and type @

Result: The user mention dialog opens but will never find a result as the complete instructional text is used as search string for a user name. The cursor is set AFTER the instructional text. On IE 11 the mention works BUT the user name is displayed at the top of the page no matter where the instructional text is positioned on the page.

This is also true for typing [ when searching for a page on a "standard" instructional text.

This makes it impossible for us to use instructional text for user guidance.