Fatal error when rich text editor is used

[halftrainedharry]

When the rich text editor is used for NewsPublisher (in the frontend)

[[!NewsPublisher?
    &initrte=`1`
    &rtcontent=`1`
    ...
]]

and a rich text editor extra (like for example "TinyMCE Rich Text Editor") is installed in the backend, a fatal error occurs:

Fatal error: Uncaught Error: Call to a member function addJavascript() on null in ...\core\components\tinymcerte\src\Plugins\Events\OnRichTextEditorInit.php:53 Stack trace: 
#0 ...\core\components\tinymcerte\src\Plugins\Events\OnRichTextEditorInit.php(41): TinyMCERTE\Plugins\Events\OnRichTextEditorInit->initTinyMCE() 
#1 ...\core\components\tinymcerte\src\Plugins\Plugin.php(50): TinyMCERTE\Plugins\Events\OnRichTextEditorInit->process() 
#2 ...\core\cache\includes\elements\modx\revolution\modplugin\22.include.cache.php(24): TinyMCERTE\Plugins\Plugin->run() 
#3 ...\core\src\Revolution\modScript.php(88): include('C:\\wamp64\\www\\m...') 
#4 ...\core\src\Revolution\modX.php(1710): MODX\Revolution\modScript->process(NULL) 
#5 ...\core\components\newspublisher\model\newspublisher\newspublisher.class.php(843): MODX\Revolution\modX->invokeEvent('OnRichTextEdito...', Array) 
#6 ...\core\c in ...\core\components\tinymcerte\src\Plugins\Events\OnRichTextEditorInit.php on line 53

The problem seems to be this line in the code:

newspublisher/core/components/newspublisher/model/newspublisher/newspublisher.class.php

Line 843 in 159898c

$this->modx->invokeEvent('OnRichTextEditorInit', $fields);

---

MODX 3.0.3-pl
NewsPublisher 3.1.5-pl

Related thread in the MODX forum:
https://community.modx.com/t/newspublisher-rich-text-editor-cant-get-it-to-work/6929