I have chosen a button from the available options in Encore. I have linked it to the timeline and everything works perfectly. But, when I click on that button, the button shifts it's position for some reason - it moves to a different spot on the screen. I can't figure out why.
You've probably moved a layer of the button (e.g. the highlight).
In the menu view, turn on the various button states (normal, highlight, select). Which one is the "moved" section.
If that is it, I would delete the button and redo.
For that menu, do "edit in photoshop." What is the pixel size of the menu?
Is this the only button?
Where are you seeing the shift? In Encore preview?
I do not see such shifts, but you may find that it does not in a burned disk. Just FYI. I would fix it; such appearances should preview correctly.