Thread:Extension talk:WYSIWYG/IE11 with MW 1.22.0 + WYSIWYG extension: Existing category definitions will corrupt after after page has been saved

IE11 problems:

Creating first initial category definition works on page where there are no categories before. After editing page with IE11 where there already is category defined, category definition will be corrupted after page has been saved.

It will be also corrupted if button "code" is pressed (to toggle between wikitext and wysiwyg view). I quess this is same kind of issue as in post by "Hoggle42 (talk)‎19:20, 20 November 2013" https://www.mediawiki.org/wiki/Extension_talk:WYSIWYG#Editor_removes_assigned_category_16286 (but I do not know if this is caused by the same reason as with IE9 explained by Hoggle42).

This is some kind of parsing error, because when i press button "Code", definition of category will be as wikitext (there is extra "|" character added).

Any ideas how we can get rid of extra "|" character with IE11? (..it works ok with Chrome and Firefox).