[wp-trac] [WordPress Trac] #52111: Classic Editor - TinyMCE Visual Page editor not working correctly after updating to version 5.6 or later

[WordPress Trac]

#52111: Classic Editor - TinyMCE Visual Page editor not working correctly after
updating to version 5.6 or later
-------------------------------------------------+-------------------------
 Reporter:  spikeuk1                             |       Owner:  (none)
     Type:  defect (bug)                         |      Status:  new
 Priority:  normal                               |   Milestone:  5.8
Component:  Editor                               |     Version:  5.6.3
 Severity:  major                                |  Resolution:
 Keywords:  needs-testing has-patch reporter-    |     Focuses:
  feedback                                       |
-------------------------------------------------+-------------------------

Comment (by azaozz):

 @floriantactisens looking at the error messages in your
 [https://core.trac.wordpress.org/ticket/52111#comment:38 previous
 comment], seems the first is related to/caused by `pixMediaInsert`. No
 idea where that code comes from though. The "Failed to load plugin..." is
 most likely caused by using a very old TinyMCE plugin and shouldn't break
 anything. Worst case of this is you could see some untranslated strings on
 some specific TinyMCE modal or button.

 The second, third and forth errors seem to refer to "missing" files/404s.
 Perhaps look in the Network tab in the browser tools for more info.

 The `<span data-mce-type="bookmark"...` comes from TinyMCE trying to keep
 the cursor position when switching from Visual to Text, but something is
 preventing it to clean the content. These spans could get saved in the DB
 when other js errors happen, and can be safely deleted.

 None of the above errors seem to be caused by core. Also switching to the
 old jQuery version with the jQuery Migrate Helper plugin should work fine.
 Perhaps look in the Network tab of the browser tools for more clues.

 @spikeuk1 right, as @floriantactisens mentioned above you can right-click
 anywhere in the browser window and select "Inspect". That will open the
 browser tools. More info on how to use them:
 https://wordpress.org/support/article/using-your-browser-to-diagnose-
 javascript-errors/#step-3-diagnosis. Could you please post what errors you
 are seeing in the console (preferably screenshots).

 In my testing 52111.diff seems to fix (or at least significantly improve)
 the initially reported problem (although I could reproduce it very rarely
 here):

  ...try to edit an existing page (or unpublished draft) the editing box in
 Visual mode is empty.
  If you click on the Text tab the content is displayed. Clicking back to
 Visual mode and the
  content is now visible.

 It also seems to fix the related #52050 and #52133.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/52111#comment:52>
WordPress Trac <https://core.trac.wordpress.org/>
WordPress publishing platform