I created these little check boxes in InDesign, basically a stroked box with a copied-from-Illustrator check mark. The box and the check are grouped and anchored to the each paragraph where the item has been completed (checked). I made sure the content of the frames were designated as graphic and not text or unassigned. I then click on the group, open object export options and assign a alt text desription (using custom setting), such as "completed" or "previiously completed", which is a gray check mark. InDesign shows the alt text, but when I export to Acrobat the PDF does not display the alt text. It sees it as a graphic but will not show the alt text that I created in InDesign.
The only way I have found to fix this is to create the entire box and check in illustrator and import as "real" graphic. This is kinda of pain to reimport and reposition all the boxes, when InDesign has the ability to create these simple graphics.
Any clue as to why Acrobat will not show the alt tags?