UI elements, buttons etc, text-input is handled by the Hildon framework automagically depending on HW and settings etc. Screen resolutions are very different on N8x0 and N900 too, so make sure you use the size constants (HILDON_SIZE_xx) since "fanger sized" button is a lot more pixels on N900 than on N8x0 (especially and issue for any bitmaps you might use in your UI).