I did consider the "clickeable part" before mentioning the transparent idea, decided it was probably not really an issue due to the following points:
* The button artist only has 24 pixels to work with when it comes to height.
+ Unless they really hate the player I doubt more than 2 lines will be sacrificed for transparency.
* Most users will "aim" for the center of the button instead of the transparent row between two buttons.
+ I doubt there will be many miss-clicks because of that. Even if it happens: Robin's design provides excellent feedback to the user they clicked "wrong".
(to be honest: this is a bit biased by the ratio between the size of my fingers and the screen size of the android devices I own
)
* I am not sure how accurate devices (or SDL) are when registering a touch (e.g. misalignment).
+ Registering a click on the transparent area might even be preferred compared to not registering a click at all (considering that the buttons provide visual feedback on their state).