UICamera's ProcessTouch will called at the beginning?

[noob22]

My button listens OnClick event.
It dont work at the beginning of appear or the first time.
Then it work well.
I tailed the code of NGUI.
UICamera's ProcessTouch function will be called at the beginning and "currentTouch.clickNotification = ClickNotification.None;" (upwards Notify OnLongPress) execute after ProcessPress function's "currentTouch.clickNotification = ClickNotification.BasedOnDelta;".
Because currentTouch.clickNotification == ClickNotification.None , so Notify OnClick dont execute.
Any suggestions？

PS：Android platform.

[ArenMook]

Click notification state begins as "always". It only gets set to "none" if you initiate a drag operation. If you find yourself initiating a drag by accident, raise your drag threshold on the UICamera.