Thanks, @Eugene D. Unfortunately, the users of our application may be pasting into any one of several target apps, not all of which can be addressed by Office Automation.
@Joost R - This has been a long-standing problem which we worked around for years by using @ChristianSchmitz 's WindowsClipboardMBS object. For whatever reason, this stopped working as of 2017r1 or 1.1. I think Christian believes it may have to do with a change in Xojo drawing on Windows.
"Paste Special" does work, though our users are not happy to have to take this extra step as the result of an "improvement" to our application. When we use the Xojo clipboard object, Excel always pastes the text, even if it's an empty string. Now, when we use the MBS object, Excel reports that it is unable to paste the picture data. So, there is apparently something in the Windows clipboard which tells the target to prefer the picture over the text, but the picture data put on the clipboard by the MBS code is currently somehow wrong.
I'll sign on to the feedback case you linked to, Joost.