diff --git a/ReText/window.py b/ReText/window.py
index <HASH>..<HASH> 100644
--- a/ReText/window.py
+++ b/ReText/window.py
@@ -843,9 +843,9 @@ class ReTextWindow(QMainWindow):
 			if mimetype is None:
 				enabled = True
 			elif markupClass == markups.MarkdownMarkup:
-				enabled = (mimetype in ("text/x-retext-markdown", "text/x-markdown", "text/markdown"))
+				enabled = (mimetype == "text/markdown")
 			elif markupClass == markups.ReStructuredTextMarkup:
-				enabled = (mimetype in ("text/x-retext-rst", "text/x-rst"))
+				enabled = (mimetype == "text/x-rst")
 			else:
 				enabled = False
 			action[0].setEnabled(enabled)
Remove support for old MIME types in export extensions

The MIME type for Markdown is documented in RFC <I>.

For reStructuredText, see:
<URL>