Unicode BiDi isolation in CSS dir property doesn't work in Internet Explorer and Microsoft Edge

Warning

The retired, out-of-support Internet Explorer 11 desktop application has been permanently disabled through a Microsoft Edge update on certain versions of Windows 10. For more information, see Internet Explorer 11 desktop app retirement FAQ.

This article discusses a by design behavior that Unicode BiDi isolation in CSS dir property does not work Internet Explorer and Microsoft Edge.

Original product version:   Microsoft Edge, Internet Explorer
Original KB number:   4459265

Symptom

When you use Internet Explorer or Microsoft Edge to open a web page that has unicode-bidi set to isolation values though Cascading Style Sheets (CSS) or the HTML dir attribute, the isolation values do not take effect. As a result, some right-to-left and bilingual text is displayed incorrectly.

Cause

Internet Explorer and Microsoft Edge currently don't support Unicode BiDi isolation.

More information

In other browsers, the dir attribute sets can be established through the following two dependent properties:

  • direction to the author-specified value
  • unicode-bidi to the isolate value

But the second action does not apply to Internet Explorer and Microsoft Edge.

Reference

For more information, see the Mozilla web pages: direction and unicode-bidi.