How to make a collider response click without blocking raycast?

[alexlange]

Hi, I'm using a red dot to remind people where they click, a collider has been put in front of everything to handle OnPress/OnDrag.
Unfortunately buttons behind it will not be clicked, I'm wondering is that possible to make the collider response without blocking the raycast go through it?

UICamera.fallthrough and UICamera.genericEventHandler seems pretty close to the answer but the former has to be set behind everything, and the latter is obsolete. 

[ArenMook]

NGUI's events don't go by collider Z. They go by widget depth (assuming the event type is set to UI type).

ALT+SHIFT+W to create a widget, ALT+SHIFT+C to give it a collider, resize to be the desired size. Use that instead of a plain collider.

[alexlange]

NGUI's events don't go by collider Z. They go by widget depth (assuming the event type is set to UI type).

ALT+SHIFT+W to create a widget, ALT+SHIFT+C to give it a collider, resize to be the desired size. Use that instead of a plain collider.

Is that possible to make a button behind another also response the click(same position but different widget depth)?

UPDATE:
Asset like EasyTouch is an easy way to handle complex touch events and it's compatible with NGUI