mysimplewp plugin dialog box displays over text

Hello,

I’m using a child version of the VW Landing Page theme.

Since the theme’s last theme update, I’ve been having problems with the mysimplewp plugin shortcode dialog box which displays over the text editing area in the Classic Editor. I didn’t mind all that much because I mostly use the Block Editor, but my customer will use the Classic Editor to add her blog content, and this issue will have to be fixed.

Another person has raised the flag in a WP support forum, but they told him that it was probably a theme issue, although he seems to be using a different theme. Can you help me fix this please? If it can be fixed with a PHP snippet, I can add it to my child theme’s function file.

Thank you!