MDHR 4.0.4 / TB136 seems not to work

Hi,

Please note first that I use a screen reader for visually impaired users. So, although the extension does not work for me, it might be functioning normally otherwise.

Ever since I upgraded to version 136 of Thunderbird and updated MDHR to 4.0.4, I've been unable to activate the preview, whether using the toolbar button or the keyboard shortcut. I have disabled/re-enabled/uninstalled/reinstalled the extension without success. I still cannot access the preview area and when I send an email to myself, the Markdown has not been converted. Is this a known issue?

Thank you!