Edge doesn't return suppported html/rtf mime types properly

Fixed Issue #9018384


Ephox D.
Sep 22, 2016
This issue is public.
Found in
  • Microsoft Edge
Fixed in build #
Reported by 1 person

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Steps to reproduce

We would like to work with you to remove flash from our JavaScript Rich Text Editor products running on Edge, whether through the reintroduction of the rich clipboard paste seen in IE11 or in a similar method to other browsers.

Ephox produces two widely used rich text editors, TinyMCE and Textbox.io. TinyMCE is the default editor in Wordpress and other popular CMS platforms. Textbox.io has been deployed to hundreds of thousands of IBM users. Across our products we estimate we have in the order of 500 million users.

When documents are copied from Microsoft Word and pasted into our editors we support importing the content with images included. In Internet Explorer 11 this was handled by the browser automatically but that functionality appears to have been removed in Edge.

As a result we had to fall back to our legacy codepath for image import. This uses a small flash object to retrieve the clipboard RTF data from which we are able to extract images. Previously this legacy codepath was used for all browsers except IE11 but we have successfully lobbied for extended clipboard support in other browsers.

We have been working with Mozilla and Google on this for the last year or so by extending the HTML clipboard paste API to include a text/rtf content type. We have been talking to Apple as well, though they’ve been quiet as usual we have had a few nibbles. Here are links to the bugs we logged:


Looking at some of the bug comments we aren’t the only company who would like access to RTF in the paste event. Support for pasting RTF clipboard data on both Windows and macOS went live with Firefox 45 earlier this year and will be live next month in Chrome 54. Once this happens, the only browsers using our legacy flash codepath will be Edge and Safari.

If you would like to see how the RTF clipboard works in Firefox and Chrome I am attaching a test case that logs RTF contents to the console when pasting. The sample document does not include images to keep the RTF data to a minimum, but the concept is the same.

To see how our flash paste works in Edge, the Textbox.io front page demo includes this feature (it’s a paid addon for TinyMCE). Insert any image into a Word document, select the entire document contents and paste into the editor.


1 attachment

Comments and activity

  • Microsoft Edge Team

    Changed Assigned To to “Brad E.”

    Changed Assigned To to “Travis L.”

    Changed Assigned To to “Amit J.”

  • If this issue is resolved, the flash crashing issue we just logged can be ignored.

    This issue is logged here:

  • Microsoft Edge Team

    Changed Assigned To to “Amit J.”

    Changed Assigned To from “Amit J.” to “Grisha L.”

    Changed Status to “Confirmed”

    Changed Title from “Help us remove the legacy flash requirement from our products” to “Edge doesn't return suppported html/rtf mime types properly”

    Changed Assigned To from “Grisha L.” to “Siye L.”

    Changed Status from “Confirmed” to “In code review”

    Changed Status from “In code review” to “Fixed”

  • Hello,

    Thank you for providing this information about the issue. We are pleased to report this feature is fixed in Edge 15063 and is available in our latest Insider Preview build.

    Best Wishes,

    The MS Edge Team

  • Yes, we have confirmed the fix. Thank you!

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