Button's appearance changed when "transition" was switched from "sprite" to "color" and again switched back to "sprite"

[shrinktofit]

Reproduce steps:

1. Create a button in editor. The transition property of button is SPRITE, by default.

2. Switch the transition property to COLOR.

3. Switch the transition property back to SPRITE again.

You can see the button's appearance mismatch after step 1 and after step 3.