Description

This issue occurs since version 2.104.0 and the introduction of new header menus and flatpages which has brought several changes to the use of TinyMCE for flatpages content edition.

Some times the TinyMCE is not loaded and the content area stays blank and is not selectable with the mouse (no cursor).

it may happen with Firefox and Chromium browsers.
in the DOM tree the iframe created for the TinyMCE editor stays empty (empty <head> and <body> tags)
I spotted a NS_ERROR_UNEXPECTED error in the console once with Firefox (see screenshot below)
the frequency is not the same between users (it happens roughly 1 every 2 times for @camillemonchicourt, 1 every 100 times for me)

error_tinymce_editor_not_loaded

NS_ERROR_UNEXPECTED error

generic Firefox error
reported to have occurred on tinymce's theme.min.js but since it is the minified version it is not helpful
lots of occurrences in TinyMCE's issues on Github but related to multiple causes. Not really helpful.

GeotrekCE / Geotrek-admin

TinyMCE editor is not loaded sometimes #4043

Description

NS_ERROR_UNEXPECTED error