PHP code shortened after page save

Hello, thanks for the plugin!

Working great for me, except for one thing:
I used the PHP everywhere field to insert a rather complex HTML form with tables and lots of embedded PHP tags. After inserting the whole code and saving the page, everything works fine.
If you edit the page again, though, parts of the code are missing from the edit field, but are displayed outside the field, somehow disturbing the wordpress backend.
If you save the page now, the incomplete PHP code will be saved, ignoring the parts displayed outside the input field. So now every time I edit the wordpress page with the PHP form on it, I have to re-enter the PHP code from an external source, which is a bit annoying.

Any ideas how to fix this? Looks to me like the code is not always escaped properly before displaying it in the backend.

https://www.ads-software.com/plugins/php-everywhere/