I had a need the other day to replicate the same row message that shows up on batch records when an error or duplicate has been encountered. It took some digging and help from a few product engineers but I finally got it working.
In my add data form spec I have the following for my load:
Then in the html file we add this css class, bbui-rowmessage-POTENTIALMATCHES, to collection div like so:
You may not need to have any code in the UIModel and may be able to get away with additional css classes on the collection div, however this set the type of message.
Once it’s built and deployed it looks like this!