XnView Software

In the attached pic you can see that I've assigned 'rainbow' as a keyword to the selected image and I am trying to search for all of the images with rainbow in the keywords.
The search comes up empty.
Bug or user error?
Thanks.

It looks like the upload failed and I'm not permitted to add another.
The image is here https://imgur.com/a/pENu6TO

you need to use 'IPTC:All fields'