Docs:
"ShowFeedback Specifies if a visual feedback should be shown for a button that has an image as background."
With the companion I do not see any feedback and testing the apk neither. So, at the moment I implemented the feedback using TouchDown and TouchUp events but of course the documentation or the implementation is wrong.
Can you tell us more about the parameters of your app? I see feedback when the theme is Classic and using the default button properties. Do you have an image on your button? Are you using another background color or shape?
Theme is Default but also with Classic does not work, yes I have an image on my button, shape should not matter as written in the docs, background color of the button is none. Well, the solution using TouchDown and TouchUp events work well, the point is that there are 3 times more code and 2 times more button graphics so no so much more development time but quite more for the graphics (that bores me a lot).
The Classic theme advice you gave me was very helpful, thank you.
If you want to use device default theme then see here for workarounds: