cannot modify the product description

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Database: MySQL 5.6.32-78.1-log
PHP Version: 5.5.22 (Zend: 2.5.0)
Zen Cart 1.5.4
Database Patch Level: 1.5.4
I use html to set up "Products Description:" but when I want to modify some item, it not shows. https://www.screencast.com/t/9r6khV6vBY
it suppose show the item description like https://www.screencast.com/t/a8GLAgBu
now I want to modify the first one. how can I do it. and can I modify from the database and where to modify it

Toggle the CK editor screen to source mode... what is there when you look at source?

You need to add HTML in Source Mode. if you paste html into CK editor in WYSIWYG mode, it will appear as lines of HTML - not as rendered HTML.

Describe how you ADD html to the product description.

How are you compiling this HTML in the first place? Are you using an external HTML editor?

HTML mode solve the problem, I forget how I set up that "product description". when I want to modify in the back end it donot have data in the description but I can see those word in front end.
so I just duplicate that item to other category and copy those "product description" from original front end then move it back
do the work, thanks

Does every product description show as blank in the admin/back end? Or just the one?