I'm having a dip into DITA with FrameMaker 11 (because that's the version I currently have).
Here's a sample topic in which I've defined a product attribute for two paragraphs:
<reference id = "id18AC90HG0CJ">
<shortdesc>Product attribute demo</shortdesc>
<title>Supported file formats</title>
When I save and reopen the topic file, the attribute values appear in XML view but not in WYSIWYG view, neither in structure view nor in the attributes pane.
Also, when I print a ditamap and apply a ditaval filter on the product attribute, I get the unfiltered output, which probably means the product attribute is ignored as well.
<?xml version="1.0" encoding="UTF-8"?>
<!-- filter.ditaval -->
<prop att="product" val="A" action="include"/>
<prop att="product" val="B" action="exclude"/>
Has this been a known bug in FM 11, or is something wrong with my configuration?
I cannot test it in FM 11 anymore because FM 12 is the oldest I have on my machine.
In FM 12, 13, 14 (2017 release), and 15 (2019 release) it works as expected. The attribute value is there in both the Structure View and the Attributes pod. I copy and pasted your code for testing.
That's good to know, thank you for testing.