Environment: Moto Glam Korean version (2.2 FROYO)
Smart keyboard Pro 4.0.2 and 3.16.0
How to reproduce:
(1) Use the Korean 단모음 keyboard on portrait layout.
(2) Set the height of the keyboard to cover approximately 1/3 of the screen (about 250 pixes, I guess.)
(3) Quickly double click a single vowel key 'ㅓ' to make a diphthong 'ㅕ'.
(4) But double click often get ignored.