Hello Syncfusion Team,
i have a razor page with multiple rich text editors.
there are all working well, but they need a custom toolbar item.
I have implemented this in the first text editor:

The custom toolbar is working well, i can add my own symbols/images from the dialog to the html content.
But: the editor that contains the custom toolbar is causing problems. i can only edit the content sporadically (for example, i cant delete the inserted images or tables), my browser console also gives me some errors as soon as i click into the text field of this editor.
Every time i click in the editor, this error is throwing:

My Toolbar (working):

Here i have recorded a video, you can see the issue in action:
https://itdocs.de/2021-07-16_10-17-20.mp4
The first editor is working well, but the last is throwing this js errors and i cant remove or edit the content well.
Can you assist me here?
Thanks,
Nils