I have a scheduled report that returns a list of distinct values. When I select the report option from within a dropdown input panel on my dashboard, then look for that report, it is not in the list. There is text "This does not contain all reports. Add a report that is not listed from Reports."
Thats it, I go to reports, and see it has run, is scheduled, etc. I can not select it though.
To add a report not listed in the dropdown click the link marked "Reports" in the message "This does not contain all reports. Add a report that is not listed from Reports." to open the reports tab. Search/Find the desired report there, click on it and use the "Add to Dashboard" option and select the existing dashboard you want to add it to.