res:dock:: fix menu position problem.

item menu covers over dock on efficient and classic mode.

tower: https://tower.im/projects/8f19f0bf0e754f0b82ef2c24bc230973/todos/a7d3af94afc34ae78d7f019c7acf11d1/

Change-Id: I215fc2c6cc77059da92065da5fa9a4477ba00bcc